Khan was born on 16 August 1970 in New Delhi, India to Mansoor Ali Khan Pataudi, a former captain of the Indian national cricket team, and his wife Sharmila Tagore, a film actress. From 1952–71, Pataudi held the title of Nawab of Pataudi, but following his death a pagri ceremony was held in the village of Pataudi, Haryana to crown Khan as the tenth Nawab of Pataudi. Khan has two younger sisters, jewelry designer Saba Ali Khan and actress Soha Ali Khan, and is the paternal grandson of Iftikhar Ali Khan Pataudi who played for the Indian cricket team in England in 1946, and Sajida Sultan, the Nawab Begum of Bhopal. Hamidullah Khan, the last ruling Nawab of Bhopal was his great-grandfather, and the cricketer Saad Bin Jung is his first cousin. Khan is of predominantly Bengali descent on his mother’s side, and on his father’s side he is of Pashtun descent.

In 1991, Khan was cast as the male lead in Rahul Rawail’s romantic drama Bekhudi (1992) alongside debutante Kajol, but after completing the first shooting schedule of the film, he was considered to be unprofessional by Rawail and was replaced by Kamal Sadanah. While filming Bekhudi, Khan met actress Amrita Singh whom he married in October 1991. Singh gave birth to their daughter (Sara Ali Khan) and son (Ibrahim) in 1995 and 2001 respectively, and the couple later separated in 2004. In 1993, Khan made his acting debut with Parampara, a drama directed by Yash Chopra. The film, which tells the story of two estranged brothers (played by Aamir Khan and Khan), failed to find a wide audience. He next appeared opposite Mamta Kulkarni and Shilpa Shirodkar in the box office flops Aashiq Awara and Pehchaan (both 1993) respectively, but Khan earned the Filmfare Award for Best Male Debut for his performance in Aashiq Awara at the 39th Filmfare Awards.

After four consecutive years of poorly received films, Khan’s career prospects began to improve in 1999; he appeared in four films: Yeh Hai Mumbai Meri Jaan, Kachche Dhaage, Aarzoo and Hum Saath-Saath Hain. The romantic comedy Yeh Hai Mumbai Meri Jaan (alongside Twinkle Khanna) and the romance Aarzoo (alongside Madhuri Dixit and Akshay Kumar) earned little at the box office, but the action-thriller Kachche Dhaage (a story about two estranged brothers becoming the target of a terrorist conspiracy) was Khan’s first commercial success since Main Khiladi Tu Anari. Directed by Milan Luthria, the film was generally well received but critics noted that Khan was overshadowed by co-actor Ajay Devgn. The feature, however, earned Khan a Best Supporting Actor nomination at Filmfare. Khan described his final release of the year, the Sooraj Barjatya-directed family drama Hum Saath-Saath Hain, as a “morale-booster”. The film featured an ensemble cast (Mohnish Behl, Salman Khan, Tabu, Karisma Kapoor and Sonali Bendre) and emerged as the highest-grossing film of the year, earning over ₹800 million (US$11 million) worldwide. During the filming of Hum Saath-Saath Hain, Khan was charged with poaching two blackbucks in Kankani along with co-stars Salman, Tabu, Bendre and Neelam Kothari. That year, he also appeared briefly in the David Dhawan-directed comedy Biwi No.1, a box office hit.

In 2001, Khan appeared in Eeshwar Nivas’ box office flop Love Ke Liye Kuch Bhi Karega, (a film loosely inspired by the 1996 black comedy Fargo) following which he featured alongside Aamir Khan and Akshaye Khanna in Farhan Akhtar’s coming-of-age dramedy Dil Chahta Hai. Depicting the contemporary routine life of Indian affluent youth, it is set in modern-day urban Mumbai and focuses on a major period of transition in the lives of three young friends. Khan played Sameer Mulchandani, a “hopeless romantic”, and was particularly drawn to the qualities of his character. Dil Chahta Hai was popular with critics and earned the National Film Award for Best Feature Film in Hindi; it performed well in the big cities but failed in the rural areas, which was attributed by critics to the urban-oriented lifestyle it presented. The feature marked a significant turning point in Khan’s career, earning him the Filmfare Award for Best Performance in a Comic Role and awards for Best Supporting Actor at the Screen, Zee Cine and International Indian Academy (IIFA) ceremonies. Rediff.com wrote that Khan was able to rise above his “under sketched character”, and the critic Taran Adarsh described him as “excellent” arguing that it was his “career-best performance”.

Following an appearance in two poorly received films: Rehnaa Hai Terre Dil Mein (2001) and Na Tum Jaano Na Hum (2002), Khan played a photographer in the second chapter (“No Smoking”) of Prawaal Raman’s anthology ensemble thriller Darna Mana Hai (2003). The film failed to find a wide audience and earned little at the box office. Bollywood Hungama described his next film, the Nikhil Advani-directed romantic drama Kal Ho Naa Ho (2003), as a “landmark” in his career. Set in New York City, it was written by Karan Johar and co-starred Jaya Bachchan, Shah Rukh Khan and Preity Zinta. With a worldwide revenue of over ₹860 million (US$12 million), the film was received favourably by critics, and became India’s second-biggest hit of the year. It also did well internationally and became the highest-grossing film of the year overseas. Khan was cast in the role of Rohit Patel—a carefree young man who falls in love with Zinta’s character—after Advani had seen his performance in Dil Chahta Hai. Writing for Outlook, Komal Nahta described Khan as a “natural” and “extremely endearing”, and Ram Kamal Mukherjee from Stardust opined that he was successful in displaying “a gamut of emotions.” Khan garnered several awards for his performance, including the Filmfare Award for Best Supporting Actor, and expressed gratitude to Shah Rukh for teaching “me so much—mainly the responsibility of the main lead”. He explained that the film’s success led to Yash Raj Films casting him in the 2004 romantic comedy Hum Tum. At the end of the year, he appeared briefly as Cpt. Anuj Nayyar in J. P. Dutta’s box office flop LOC Kargil.

For his next release, Khan featured in a starring role opposite Rani Mukerji in Kunal Kohli’s Hum Tum, a romantic comedy about two headstrong individuals who meet at different stages of their lives. He was cast in the role of Karan Kapoor (a young cartoonist and womaniser) after Aamir Khan was unable to do the film; Kohli said, “I realised that the role needed a younger man […] someone who could present a more youthful picture. Saif has this unique quality, he can play a 21-year old as well as a 29-year old and was ideal for [the film].” With a worldwide revenue of ₹426 million (US$6.0 million), the film proved one of the biggest commercial successes of the year and Khan’s first success in which he played the sole male lead. Rediff.com wrote about his performance: “Saif reprises his urbane self from Dil Chahta Hai and Kal Ho Naa Ho, peppering it with occasional fits of introspection and angst, and marking himself as an actor whose time has come.” He won the Filmfare Award for Best Performance in a Comic Role and was conferred the National Film Award for Best Actor at the 52nd National Film Awards among much controversy. It marked the beginning of his work with Yash Raj Films, one of the largest production houses in Bollywood. In 2004, Khan began dating model Rosa Catalano whom he separated with three years later.

In 2005, Rediff.com published that Khan had established himself as a leading actor of Hindi cinema with starring roles in the drama Parineeta and the comedy-drama Salaam Namaste. An adaptation of Sarat Chandra Chattopadhyay’s 1914 Bengali novella by the same name, Parineeta was directed by Pradeep Sarkar, and narrated the love story of an idealist (Lalita, played by Vidya Balan) and a musician (Shekhar, played by Khan), the son of a capitalist businessman. Although the film’s producer, Vidhu Vinod Chopra, considered Khan to be too inexperienced for the part, he was persuaded by Sarkar who felt that Khan was perfect for the role. The film garnered critical acclaim upon release and Khan’s portrayal earned him his first Filmfare nomination for Best Actor. Derek Elley from Variety wrote, “Khan, who has gradually been developing away from light comedy, again shows smarts as a substantial actor.” Siddharth Anand’s Salaam Namaste became the first Indian feature to be filmed entirely in Australia and went on to become the year’s highest-grossing Bollywood production outside of India with worldwide ticket sales of ₹572 million (US$8.0 million). The film tells the story of a contemporary cohabiting Indian couple and their subsequent struggle with an unexpected pregnancy. Khan played the role of Nikhil Arora, a single modern young man who leaves India to make his own life in Melbourne. The critic Taran Adarsh praised Khan for delivering his third successive performance and Khalid Mohamed noted that he “rescues several untidily written scenes with his neat wit and that flustered […] facial expression.”

Alongside his acting career, Khan has participated in several concert tours and televised award ceremonies. He performed in his first concert tour, “Temptations 2004”, with actors Shah Rukh Khan, Rani Mukerji, Preity Zinta, Arjun Rampal and Priyanka Chopra. Showcased in over 22 countries across the world, it became Bollywood’s most prominent international concert to that point. In December 2005, Khan performed alongside the band Parikrama at the Mittal Gardens in New Delhi, and later reunited with them and Strings for “The Royal Stag Mega Music Concert” (a four-city concert tour) two years later. The following year, he was part of the “Heat 2006” world tour, along with Akshay Kumar, Preity Zinta, Sushmita Sen and Celina Jaitley. He later performed along with several other Bollywood personalities at the closing ceremony of the 2006 Commonwealth Games.

By 2007, Khan was keen on branching out into film production to “explore various genres of commercial and intellectually stimulating cinema”. The critical success of Being Cyrus led him to create Illuminati Films and partner up with producer Dinesh Vijan, someone whom he shared a “like-minded perspective and ideology […] with regard to cinema”. Khan next reunited with producer Vidhu Vinod Chopra in the epic drama Eklavya: The Royal Guard (2007), alongside Amitabh Bachchan, Boman Irani, Sharmila Tagore and Vidya Balan. Set in the state of Rajasthan during the early years of Indian independence, the movie revolves around a jealous and ungrateful ruler and his ailing wife. Although the film did not succeed at the box office, it was chosen as India’s official entry to the Oscars. BBC Online described the film as a “cinematic experience” and praised Khan’s growth as an actor, particular noting his scene with Bachchan’s character. Following an appearance in the poorly received action-comedy Nehlle Pe Dehlla (a production that had been delayed since 2001), Khan featured opposite Rani Mukerji in the family drama, Ta Ra Rum Pum (2007). Directed by Siddharth Anand, it received mixed reactions from the critics but earned over ₹690 million (US$9.7 million) in India and abroad. Writing for Hindustan Times, Khalid Mohamed praised Khan for displaying a new maturity but Rajeev Masand thought that neither he nor Mukerji “are able to make much of an impression because their characters are so unidimensional and boring.”

Starting in 2007, Khan’s relationship with Kareena Kapoor became one of the country’s most-reported celebrity stories, and they were listed amongst the top celebrity couple endorsers for brands and products worldwide. In a blog published by The Wall Street Journal, Rupa Subramanya described their marriage as India’s “wedding and social event of the year”. Kapoor gave birth to their son Taimur in December 2016. From 2012–19, Khan has featured on Forbes India’s “Celebrity 100,” a list based on the income and popularity of India’s celebrities. He peaked at the fifteenth position in 2012 and 2014 with an estimated annual earning of ₹642 million (US$9.0 million) and ₹629 million (US$8.8 million) respectively. In 2003, Khan placed fourth on Rediff’s list of “Top Bollywood Male Stars”. He was later ranked second in 2005, sixth in 2006 and seventh in 2007. In March 2011, Khan placed fifth on Rediff’s list of “Top 10 Actors of 2000–2010”. He was ranked among the top 30 on The Times of India’s listing of the “Most Desirable Men” from 2010 to 2015, and has additionally featured in the UK magazine Eastern Eye’s “World’s Sexiest Asian Men” list in 2008, 2011 and 2012. In 2010 and from 2012–14, Khan was featured as one of the best-dressed male celebrities by the Indian edition of GQ magazine.

Khan received further success in 2008, starring in the Abbas-Mustan thriller Race with an ensemble cast including Anil Kapoor, Akshaye Khanna, Bipasha Basu, Katrina Kaif and Sameera Reddy. The feature was loosely adapted from the 1998 American film Goodbye Lover, and became one of the biggest box office hits, earning ₹1.03 billion (US$14 million) worldwide. CNN-IBN’s Rajeev Masand found Khan to be a standout among the ensemble, adding that he has “the least dialogue but the one who makes the best impression”. This was followed by three projects produced by Yash Raj Films: the action-thriller Tashan, the fantasy-drama Thoda Pyaar Thoda Magic, and the animated film Roadside Romeo, all of which were not successful.

In 2009, Khan appeared in the romantic drama Sanam Teri Kasam, a production that had been delayed since 2000. The film garnered negative reviews and poor box office returns. Khan’s role was small, and not well received. He next starred in his company’s first project: Love Aaj Kal (2009), a romantic drama from the writer-director Imtiaz Ali. Featured opposited Deepika Padukone, the film documented the changing value of relationships among the youth, and Khan played dual roles—the younger part of Rishi Kapoor’s character (Veer Singh) and Jai Vardhan Singh, an ambitious architect. Love Aaj Kal received mostly positive reviews by critics and became one of the highest-grossing films of the year, earning over ₹1 billion (US$14 million) worldwide. Gaurav Malani of The Economic Times described his performance as “refreshing natural” and “outstanding”. At the 55th Filmfare Awards, the feature was nominated for Best Film and Khan received an additional nomination for Best Actor.

He next played the protagonist in the English language art film, Being Cyrus (2006), co-starring alongside Naseeruddin Shah and Dimple Kapadia. Directed by debutant Homi Adajania, the psychological drama revolves around a dysfunctional Parsi family with who Khan’s character moves into. The film received predominantly positive reviews, and Khan was particularly praised. Later in the year, he portrayed the character of Iago in Omkara, the Indian adaptation of William Shakespeare’s Othello. Directed by Vishal Bhardwaj, the film is a tragedy of sexual jealousy set against the backdrop of the political system in Uttar Pradesh. The film premiered at the 2006 Cannes Film Festival and was also selected for screening at the Cairo International Film Festival. Omkara was received positively by critics, and Khan went on to receive major acclaim earning the awards for Best Performance in a Negative Role at the Filmfare, Screen, Zee Cine and IIFA ceremonies; his performance was later included in the 2010 issue of the “Top 80 Iconic Performances” by Filmfare. Variety described it as a “powerhouse performance” and wrote that “[i]t is Khan’s movie through and through, in a performance of rugged, contained malevolence which trades on his previous screen persona as a likable best friend as well as his stint as the manipulative outsider in Being Cyrus. It is smart casting, superbly realized.”

In 2011, he appeared in Prakash Jha’s multi-starrer drama Aarakshan. Set in the city of Bhopal, Madhya Pradesh, the film deals with the policy of caste-based reservations in government jobs and educational institutions. Khan portrayed the character of Deepak Kumar, a rebellious student who joins the mafia. To prepare for the role, Khan was required to take acting workshops along with the rest of the cast. Prior to its release, the film was banned from releasing in select cities across India due to its controversial subject. While the film received a mixed critical reaction, his performance was generally well received. The following year, Khan produced both of his films. For his first release, he collaborated once again with director Sriram Raghavan, as the protagonist in the action thriller Agent Vinod. Khan described it as his “most ambitious project”, but the film opened to mixed reviews and eventually under-performed at the box office grossing ₹400 million (US$5.6 million) in India on a budget of ₹620 million (US$8.7 million).

Since October 2011, Khan has taken the responsibility of managing his father’s eye hospital and has also made public appearances to support various other charitable causes. In February 2005, Khan and several other Bollywood actors participated in the 2005 HELP! Telethon Concert to raise money for the victims of the 2004 Indian Ocean earthquake and tsunami. He took part in a charity cricket match organised by IIFA at Headingley Cricket Ground in West Yorkshire, England in 2007, and later hosted an event organised by the award ceremony to help raise funds for various charities in 2011. In November 2008, Khan performed in a concert to raise money for the victims of the 2008 Bihar flood and in September 2013, he attended a charity dinner organised by The Venu Eye institute, donating two of his personal belongings to help raise funds for cataract operations. Later that year, he spent time with underprivileged kids during the filming of Bullett Raja. In October 2014, Khan was appointed as an ambassador for Olympic Gold Quest and donated ₹2 million (US$28,000) to help raise funds for the training of athletes.

In his following release, Homi Adajania’s romantic comedy Cocktail, he featured as the software engineer Gautam Kapoor. Set in London, the film follows the story of Khan’s character and his relationship with two temperamentally different women—an impulsive party girl (Veronica, played by Deepika Padukone) and a submissive girl next door (Meera, played by Diana Penty). Khan described the project as “a love story with a modern sensibility and treatment”, and agreed to produce and feature in the film after his role was declined by Imran Khan. Critics were divided in their opinion of the film, but it emerged a financial success grossing over ₹1.2 billion (US$17 million) worldwide. Gaurav Malani of The Times of India described Khan’s performance as “effortless” and noted that he was in his “comfort zone”. On 16 October 2012, Khan married actress Kareena Kapoor (after a five-year courtship) in a private ceremony in Bandra, Mumbai, and a reception was later held at The Taj Mahal Palace Hotel and the Lutyens Bungalow Zone in Mumbai and Delhi respectively.

In an interview with The Times of India, Khan explained that he regretted starring in the 2014 Sajid Khan-directed comedy Humshakals. Co-starring alongside an ensemble cast (Ritesh Deshmukh, Ram Kapoor, Bipasha Basu, Tamannaah and Esha Gupta), Khan portrayed three different characters in an attempt to “expand my market” and step out of his comfort zone. The Hindustan Times described it as a “dim-witted comedy” and criticised Khan for being “the worst thing about [the film].” He next produced and featured in Happy Ending (2014), a romantic comedy directed by Raj Nidimoru and Krishna D.K. NDTV’s Saibal Chatterjee found Khan’s character of a struggling writer to be “a breezy rejig of his Hum Tum and Salaam Namaste persona of a decade ago”, and noted that “the many collegiate hook-ups and break-ups he pulls off in Happy Ending do not look completely at odds with the film’s purpose.” Both Humshakals and Happy Ending underperformed at the box office.