In February 1994, Levine, along with friends Jesse Carmichael, Mickey Madden, and Ryan Dusick formed garage band Kara’s Flowers. In 1995, the group played their first gig at the Whisky a Go Go, a nightclub in West Hollywood, California, with Levine performing vocals and guitar. The band was discovered while they were performing in Malibu by independent producer Tommy Allen, who along with his partner John DeNicola, had them record an 11-track album. Owing to a string of industry showcases in Los Angeles, they were signed on to Reprise Records through producer Rob Cavallo. In August 1997, the band released their first album, titled The Fourth World and also appeared on an episode of the drama series Beverly Hills, 90210. Despite high expectations, it had little success, selling about 5,000 copies. Reprise decided to drop the band after Cavallo’s exit from the label Disappointed with the results of their album, the band broke up. Later, Levine would say of the experience: “Kara’s Flowers was just floating up the wall beneath the sticks. Make a record quickly, put it out. No touring base, no nothing. Just try to make it happen right out of the gate and it just doesn’t work”.

After the break up of Kara’s Flowers, Levine, along with Carmichael, left Los Angeles to pursue higher studies at Five Towns College in New York. On MTV News, in 2002, he said: “That’s when I started waking up to the whole hip-hop, R&B thing. We had friends named Chaos and Shit. It was not Brentwood High”. They dropped out after a semester, and reunited with Madden and Dusick to form a band once more. They experimented with several styles, including country and folk, before deciding groove-based music would become their genre. Levine explained the need for a makeover for the band: “We were just so sick of being a typical rock ’n’ roll band … I felt like I needed to look elsewhere for vocal inspiration.” The band put together a demo that was rejected by several labels, before it caught the attention of Octone Records executives James Diener, Ben Berkman, and David Boxenbaum. Following Berkman’s advice, the band added a fifth member, James Valentine, and was renamed Maroon 5. In an interview with HitQuarters, Berkman explained that Levine “seemed to be a very shy, shoe-gazing type … a fifth member could play the guitar to free up the singer [Levine], so he could be the star I perceived him to be”.

Around this time, Levine had been working as a writer’s assistant on the CBS television show Judging Amy; the progam’s producer Barbara Hall was his family friend. While on the show, he would spend time writing songs about his ex-girlfriend. These songs were put into Maroon 5’s debut album Songs About Jane, which was released in June 2002. The album slowly gained airplay, and eventually became a sleeper hit, selling an estimated 10 million copies and becoming the tenth best-selling album of 2004, two years after its release. In 2005, Maroon 5 won their first Grammy Award, for Best New Artist. The next year, they won the Grammy Award for Best Pop Performance by a Duo or Group with Vocals for the second Songs About Jane single “This Love”.

Levine has collaborated with several musical artists. In 2005, he was featured on the song “Live Again” by hip-hop duo Ying Yang Twins. The same year, he appeared on Kanye West’s album Late Registration, on the third single “Heard ‘Em Say”, a collaboration Levine called “very pure and very easy”. The song was created during an airplane flight that he and West shared, and its refrain was later used for the Maroon 5 song “Nothing Lasts Forever” from It Won’t Be Soon Before Long. He also appeared on Alicia Keys’ third album Alicia Keys: MTV Unplugged, as part of the cover of The Rolling Stones song “Wild Horses”. Around the same time, he featured on fellow Octone Records singer K’naan’s single “Bang Bang”. In 2009, he recorded “Gotten”, a song for Slash’s first solo album Slash (2010). In February 2010, he was among approximately 80 musicians who sang on the charity-single remake of “We Are the World”, called “We Are the World 25 for Haiti”. In 2011, he appeared on the Gym Class Heroes song, “Stereo Hearts”. Levine also worked with hip-hop artist 50 Cent on his song “My Life”, recording the vocals almost two years before it was released as a single in 2012, which included rapper Eminem. In 2013, Levine wrote a song with Swedish composer Ludwig Göransson called “My Most Terrible Secret” by the cast of Community, in the episode from the television series “Intro to Felt Surrogacy”. In 2015, Levine was featured on the song “Painkiller” by Rozzi Crane and the duo, R. City’s single “Locked Away”. In 2016, Levine collaborated with The Lonely Island for the song “I’m So Humble”, on the soundtrack album Popstar: Never Stop Never Stopping, which they also appeared in the film of the same name. In April 2019, Levine and 29 other musical acts were featured on the charity single “Earth”, which raises climate change awareness. In late 2019, Levine collaborated with American actor and musician Joe Pesci, on his third album Pesci… Still Singing, with two songs “Baby Girl” and a cover of Stevie Wonder’s “My Cherie Amour”. In 2020, Levine was featured in the song “Trust Nobody”, with rapper Lil Wayne on his 13th studio album Funeral (2020).

By 2006, the band began recording again, and in May 2007, Maroon 5’s second album It Won’t Be Soon Before Long was released. Levine described the album as “a vast improvement”, explaining: “I think this record is a little more self-confident and powerful lyrically”. To support the album, the band performed on a “six-date club tour” in which they visited small venues in Boston, San Francisco, Los Angeles, Minneapolis, Miami, and New York City in early June 2007. The album and its lead, third and penultimate singles (“Makes Me Wonder”, “Won’t Go Home Without You” and “If I Never See Your Face Again”, respectively) each received Grammy nominations, although only “Makes Me Wonder” secured a win.

In 2007, Levine had stated that he believed Maroon 5 was reaching its peak and might make one more album before disbanding. He was quoted explaining: “Eventually I want to focus on being a completely different person because I don’t know if I want to do this into my 40s and 50s and beyond”. But in 2010, he dispelled any rumors of the band breaking up, saying:”I love what I do and think that, yes, it might be tiring and complicated at times [but] we don’t have any plans on disbanding any time soon”. He has also turned down the idea of having a solo career, stating that “there will never be a solo record. I would sooner have another band”. On February 10, 2017, Levine received a star on the Hollywood Walk of Fame for his contributions to the recording industry.

Levine has made four notable comic appearances on television. During 2007, he appeared in the 33rd-season premiere of Saturday Night Live in an SNL Digital Short called Iran So Far, performing with Andy Samberg, Fred Armisen and Jake Gyllenhaal. Levine played himself while singing a humorous bridge to a “love song” for Mahmoud Ahmadinejad. In 2008, he performed on Comedy Central’s “Night of Too Many Stars”. He also had a cameo on Jimmy Kimmel Live! for the night of stars and endorsed Barack Obama in the 2008 Presidential Election. In 2013, he hosted Saturday Night Live and featured alongside Kendrick Lamar on Lonely Island’s digital short “YOLO”, which parodies the acronym for “You Only Live Once.” His hosting was generally disliked by reviewers, who called it “mediocre” and “subpar.”

In October 2008, Levine collaborated with First Act to create the First Act 222 Guitar, which was fashioned to his specifications. The guitar was sold via Target stores. Two years later he launched his own fashion line, entitled “222”, at the Project Trade Show in Las Vegas. The collection features jeans, basic T-shirts and leather jackets. The venture was organized in partnership with his father, Fred Levine (who operates a chain of specialty boutiques), and his cousin, Sami Cooper.

After winding down from a world tour in support of It Won’t Be Soon Before Long, the band began recording in Switzerland in 2009, in collaboration with record producer and songwriter Robert John “Mutt” Lange. Levine said Lange “worked me harder than anyone ever has”. In 2010, Maroon 5 released their third studio album, Hands All Over. The album did not initially meet expectations. In an interview with Los Angeles Times, Levine explained that the album suffered from being “all these disparate ideas and songs that didn’t make any sense together”. After the moderate success of the album’s first three singles, the band released “Moves like Jagger” which Levine classified as “one of those songs that was definitely a risk; it’s a bold statement”. The single became a worldwide success; it was the ninth-best-selling digital single of 2011 with sales of 8.5 million copies and, as of 2012, the eighth-best-selling digital single of all time. Levine later credited the song with “totally reviving the band”.

In early 2010, while performing at the Sports Illustrated Swimsuit Issue release party in Las Vegas, Levine met Russian Sports Illustrated swimsuit cover-model Anne Vyalitsyna. They began a relationship. They ended the relationship in April 2012 in an “amicable and supportive manner”.

In 2011, Levine has served as a contestant judge/coach on the reality talent television show, The Voice. The contestants of his team named Team Adam, who won in the series are Javier Colon (season 1), Tessanne Chin (season 5) and Jordan Smith (season 9). The Voice has been credited with reviving Maroon 5’s “faltering” career after the sub-par sales of Hands All Over as well as increasing Levine’s popularity. According to polling firm E-Poll Market Research, awareness of Levine has nearly tripled since he joined the show. He has also been described as the “breakout” star of the series, with #TeamAdam and @AdamLevine scoring a respective 203,000 and 2.14 million Twitter mentions in the show’s third season, higher than all the other coaches. In 2013, The Hollywood Reporter estimated that Levine was paid $10–12 million for each season of The Voice. In May 2019, Levine left the series after sixteen seasons and eight years since his debut in 2011.

In June 2011, Levine took part in an educational campaign to raise awareness of attention deficit hyperactivity disorder (ADHD). The project, titled “Own It”, was created by Shire and organized in collaboration with the Attention Deficit Disorder Association (ADDA), Children and Adults with attention deficit hyperactivity disorder (CHADHD). The project targets people who were previously diagnosed with the disorder, focusing on how it may continue into adulthood. Levine, who himself was diagnosed with ADHD as a teenager, said: “This campaign is important to me because it can help young adults and adults realize that there’s a chance they may still have ADHD if they had it as a kid”. In connection to this, he wrote an article in ADDitude Magazine about his personal experience with it.

Levine, whose brother Michael is gay, is a supporter of same-sex marriage and LGBT rights. In 2011, he made a video on Maroon 5’s official YouTube account in support of the It Gets Better Project. In January 2012, he announced that Maroon 5 had changed the location of their post-Grammy Awards show because of the “unnamed Los Angeles restaurant’s backing of Proposition 8”.

In 2012, Levine appeared as a recurring character in American Horror Story: Asylum, the second season of the television series American Horror Story. He plays Leo Morrison, a newly-wed photographer visiting modern-day Briarcliff Manor, an insane asylum, on honeymoon with his wife, played by Jenna Dewan. The scenes were shot around his band’s summer touring schedule. In an interview with E!, he said of his role: “It sounded like so much fun and that’s why I wanted to do it … this sounds, like, hysterical, funny, dark and cool and right up my alley”. However, he admitted to not being a fan of the show nor horror genre in general, stating he didn’t watch the episodes because “it’s just so weird and disturbing”.

In June 2012, Levine was cast in the musical romance-drama film Begin Again (originally titled Can a Song Save Your Life?). The film was directed by John Carney and Keira Knightley and Mark Ruffalo acted in the lead roles. In it, he plays Dave Kohl, Knightley’s songwriting partner and former boyfriend of five years, who leaves her behind on finding success in the music industry. The film premiered at the 2013 Toronto International Film Festival to generally favorable reviews from critics.

Levine founded his own record label, 222 Records in February 2012. He stated that he was inspired to start the label to sign on Rozzi Crane, an USC music student he discovered through a mutual friend. She became the first singer signed on to the label, followed by Glee actor Matthew Morrison, Mexican artist Diego Boneta, and The Voice season 2 contestant and part of Team Adam, the singer Tony Lucca. It was reported that he was negotiating further with potential distributors, as well as organizing staff, to operate as a full-fledged record company with departments such as marketing, radio and publicity.

In September 2012, Levine was in the Philippines to collaborate with the clothing company Bench; they launched the menswear collection. In January 2013, Levine announced he would be enter a partnership with Sears Holdings to launch a multi-department lifestyle brand of apparel and accessories collections. The company owns Kmart and ShopYourWay, a shopping social platform; it also includes rapper Nicki Minaj in the same contract. The menswear collection was launched on October 1 that year and conducts business via 500 Kmart stores across the US, as well as online. In an official statement, Levine said: “Partnering with ShopYourWay to develop this line was an exciting opportunity for me and I am really looking forward to diving into the process of designing an apparel and accessory collection”. In an interview with People, he commented further, “it was cool that they really promoted creative control. I like to be involved with process rather than just phoning it in”. Later, Levine became a celebrity spokesperson for Proactiv. In the commercial, Levine shares details about his acne experiences in high school, and promotes Proactiv Plus.

In May 2012, Levine began dating Behati Prinsloo, a Namibian Victoria’s Secret model. The couple married on July 19, 2014, with Jonah Hill officiating the wedding. Levine and Prinsloo have two daughters, Dusty Rose (born September 21, 2016) and Gio Grace (born February 15, 2018).

In November 2013, Levine was named People magazine’s Sexiest Man Alive, becoming the first singer and the second non-actor (after John F. Kennedy, Jr.) to claim the title. He was ranked No. 41 on Glamour’s “Sexiest Men of 2012” list. In 2008, he appeared on People’s “Single and Sexy Men” list. He was elected TV’s Most Crushworthy Male Reality Host/Judge in a poll held by Zap2it. In April 2012, Shalom Life ranked him Number 7 on its list of “Top 50 Hottest Jewish men in the world”. Levine stripped naked for testicular cancer awareness for a centerfold in Cosmopolitan UK’s February 2011 issue.

In 2013, Levine started a production company 222 Productions and the first project was Sugar (2018), a YouTube Premium web television series which was inspired by the music video for the Maroon 5 song of the same name. It follows music artists to crash events for unsuspecting fans. The company produced a reality competition series Songland, which premiered on NBC on May 28, 2019, where Levine served as executive producer. The company signed a deal with Wheelhouse Entertainment.

Levine collaborated with ID Perfumes to create his debut eponymous scent. The line was launched at the Premiere Fragrance Installation in Los Angeles in February 2013. The fragrance range, consisting of scents for both for men and women, is sold through Macy’s department stores in microphone-shaped bottles. Speaking at its launch, Levine said: “The task was to make something that I would wear. So that was a process and we finally came to a great conclusion and it smells great” The fragrance garnered media attention for contradicting his tweet the previous year, in which he said that he wanted to “put an official ban on celebrity fragrances. Punishable by death from this point forward”. In January 2020, Levine announced that he is the new Ambassador of the brand Shure for the wireless earphones and headphones, the Aonic 215 and 50, is available on electronic stores on April 2, 2020.

In 2013, Levine was mentioned in a hostile work environment lawsuit filed in Los Angeles Superior Court by an unnamed security guard who claimed that Universal Music Publishing Group’s Santa Monica location was “infiltrated with pervasive drug use where you could smell marijuana seeping from various offices and openly used in common areas, and lounges”. The guard claimed that when she complained about the cannabis smoke coming from one of the studios, she was told that “it’s Adam Levine … if he wants to come to the lobby and do a line of cocaine on the floor, it’s OK”. In an official statement to The Hollywood Reporter, UMPG (Universal Music Publishing group) described the allegations as “absurd”.

In 2014, Maroon 5 continued their collaboration with Ryan Tedder, Max Martin and others to release their fifth studio album V (pronounced: “five”). Levine acknowledged that they followed the same song-writing process that they tried with Overexposed, saying: “We developed a really nice system on the last record — we found songs we were passionate about, developed them and put our stamp on them […] this time we kept it going but looked for different types of songs.” Five singles were released from it. In support of the album, the band undertook the Maroon V Tour, which kicked off with a show in Dallas in February 2015.

In July 2020, Levine and Prinsloo collaborated with Ferrari and Save the Children to raise funds to support U.S. education programs during the COVID-19 pandemic.