In June 2004, the month after his tenth birthday, he won the platform competition in the National Junior (under-18) group, making him the youngest winner of that event. In 2005 Daley competed as a guest competitor in the Australian Elite Junior Nationals and placed first in platform and second in 3 m springboard in the 14–15 age group event. He also competed in the 14–15 category at the 2005 Aachen Junior International, placing second in platform and third in 3 m springboard. He met the qualification standard for the 2006 Commonwealth Games, but was not selected for the England team because of his age. In 2006, he was the under-18 British champion in platform and 3m springboard, and he placed second in the 10 m platform at the 2007 senior British Championships, which were held in December 2006.

In January 2007, at the age of twelve, Daley was given a special dispensation to compete at the 2007 Australian Youth Olympic Festival. The usual minimum age is fifteen. Competing with a persistent thumb injury, Daley won the silver medal with synchro-partner Callum Johnstone in the 10m synchronised-diving final.

Later in 2007, he won the senior platform title at the Amateur Swimming Association (ASA) National Championships, the national championship for English divers. In 2007 he also began to compete on International Swimming Federation’s (FINA) international diving circuit of Grand Prix and World Series events, twice finishing fourth in individual competition.

In January 2008, Daley won the 10m platform event at the British Championships and become the youngest winner of the senior British 10 m title. He also won the 10 m platform synchro title with new partner Blake Aldridge.

Two weeks later, Daley won his first medals on the FINA circuit, winning a bronze in the individual platform competition and a silver in synchro at the Madrid Grand Prix. Daley and Aldridge won bronze in synchro at the 2008 FINA Diving World Cup. Their score was a British record and Daley became the youngest ever male medallist in a world diving event. Daley came seventh in the individual competition. In March 2008, Daley became the youngest person to win a gold medal at the European Championships, held in Eindhoven. The previous youngest winner was the Scottish swimmer Ian Black, who won a European gold in 1958 at the age of 17.

From age 11 to 14 Daley attended Eggbuckland Community College. At 13 he became a celebrity supporter of ChildLine, a children’s helpline run by the National Society for the Prevention of Cruelty to Children (NSPCC), and at that time it was revealed that he had been bullied eighteen months earlier. In April 2009, Daley alleged to Plymouth’s main local newspaper The Herald that he had been bullied at school since the Olympics, and his father told the BBC that he had temporarily withdrawn him from that school because its response to the problem had been ineffective. Daley was praised in the media for speaking out about his problem.

In February 2009, Daley retained his individual British 10m championship, setting a competition personal best score of 517.55 points, 133.45 points ahead of the second-placed diver. He was unable to defend his 10m synchronised title, as his dive partner Blake Aldridge had been injured in a brawl at a nightclub several days before the championships and was unable to dive. In March 2009 he improved his personal best to 540.70 in coming third at a Diving World Series event in China, and the following month he improved it to 540.85 while finishing second at the World Series event in Sheffield.

During the Olympics Daley had a row with diving partner Blake Aldridge when the latter phoned his mother between rounds. When Aldridge missed the British Championships because of the injury sustained in the nightclub incident, Daley’s father said he’d like his son to have a different diving partner. In April 2009 he started to dive with Max Brick, who is two years his senior, compared with the twelve-year gap with Aldridge. The pair achieved a silver medal in the 10m synchronised event at Fort Lauderdale on 8 May 2009. Daley won the individual event in a new personal best of 554.90, scoring a perfect set of seven 10s for one of his dives.

In the 2009 FINA World Championships, held in Rome, Daley unexpectedly won the individual platform title despite his lower tariff, with a score of 539.85 points, when his opponents had poor final dives – Qiu Bo finished on 532.20 points, Zhou Luxin on 530.55. In the 10 m platform synchronised event at the World Championships, Daley and Brick finished in 9th place following an inconsistent series of dives by the new pairing.

In August 2010, Daley attended the European Championships in Budapest, Hungary, intending to defend his individual 10m title. However, an injury to his triceps muscle in the 10m synchro competition forced his withdrawal from the synchro and individual 10m competitions, and placed his participation in the inaugural Youth Olympics in Singapore in the following two weeks in doubt. It was later announced that Daley would dive in the 3m springboard but not in the 10m platform. Daley took part in the 3m springboard diving competition and finished in 9th place.

On 12 October 2010, Daley attended the 2010 Commonwealth Games in New Delhi, India. He and his teammate Max Brick won the gold medal for Synchronised 10m Platform Competition. The following day he also won gold in the 10m Individual Platform competition.

In November 2010, Daley was announced as a nominated sportsman for the BBC Sports Personality of the Year 2010 and the BBC Young Sports Personality of the Year 2010. He won BBC Young Sports Personality of the Year 2010 for the third time in his career, and is the first person to receive this award three times.

Daley created a YouTube channel on 23 August 2010. His channel consists of vlogs, exercises, food, etc. As of 2019, Daley has over 800,000 subscribers with over 100 million views. On 2 December 2013, Daley released a YouTube video announcing that he had been in a relationship with a man since early that year. He said: “I’ve never been happier.” Daley said that it had been a tough decision to speak out about his private life. He said: “I’d never felt the feeling of love, it happened so quickly, I was completely overwhelmed by it to the point I can’t get him out of my head all the time.” His spouse is American film screenwriter, director and producer Dustin Lance Black.

Daley was born in Plymouth, Devon, England, the son of Debbie (née Selvester) and Robert Daley. He has two brothers – William who is three years younger, and Ben who is five years younger. Their father, Robert, died from a brain tumour on 27 May 2011, aged 40, just a few days after Daley’s 17th birthday.His early diving hero was Canadian diver Alexandre Despatie, who won gold at the 1998 Commonwealth Games at the age of 13, and British diver Leon Taylor, who later mentored him. Daley was spotted by a coach, taking part in regular diving lessons, and was placed in a competitive squad in September 2002. His first competition was the National Novice Championships in April 2003 where he won a medal in the 8/9-year-old boys category. In September 2003, he took part in an invitational event in Southampton where he won the 1 m, 3 m and platform events, and first made his mark on the wider audience. Daley won his age group at the British Championships in the 1 m springboard, the 3 m springboard, and platform in 2004, 2005, and 2006.

For the 2011 season, Daley was paired in the synchronised competitions with 2004 Athens Olympic silver medallist Peter Waterfield in British Swimming’s continuing efforts to find the best synchro pairing for the 2012 Olympics. At the 2011 National Cup, the British Championship was held in the new Southend Swimming and Diving Centre on 28–30 January and Daley came second in the 3m springboard competition behind Jack Laugher. With Waterfield, he won the 10m platform synchronised competition. The following day, Waterfield beat Daley to the individual 10m platform title for the second successive year, by 494.25 points to 472.35, with Max Brick third with 399.80.

In the 2011 World Championships, held in Shanghai, China, he was again paired with Waterfield in the 10m synchro event. In the week before the competition Waterfield was struck by a flu-like illness for five days, and consequently they finished in sixth place. In the individual event, Daley finished in fifth place on 505.10 points, behind Qiu Bo (585.45), David Boudia (544.25), Sascha Klein (534.50), and Victor Minibaev (527.50).

On 27 July 2011, Daley took the first dive in London’s newly built Olympic Park Aquatics Centre marking the one year countdown until the games begin. It was broadcast live on BBC One and when interviewed he said “Marking the one year to go, by diving in the Aquatics Centre is an incredible honour. Only a few years ago, this was a distant dream. The fact that I qualified at the weekend and am taking the first dive is a complete privilege. I can’t wait for next year and the honour of representing Team GB.”

In 2012, Daley finished his two-year A-level studies in mathematics, Spanish and photography. Daley decided not to undertake an International Baccalaureate course because of the pressures he faced in his preparation for the 2012 Olympics. He received an A* in his Photography A-level, and an A in his Spanish and Maths A-levels.

In the 2012 season, a thumb injury forced Daley’s withdrawal from the National Cup a few days before the competition (the 10m platform title was won by Max Brick). In February 2012 British Diving’s Performance Director Alexei Evangulov criticised Daley’s work ethic, stating that he feared Daley’s media and commercial activities were to the detriment of his training for the Olympics – a comment which was seemingly backed up when Daley and Pete Waterfield could only finish 7th in the 10m synchro competition in the FINA World Cup event held at the London Aquatics Centre.

Following a clear-the-air meeting between Daley, Evangulov, and Daley’s representatives, Daley participated in the 2012 FINA Diving World Series. In the first event held in Dubai, Daley and Waterfield finished 4th in the 10m synchro event, while Daley won silver in the individual 10m event. In the event held in Beijing a week later, Daley and Waterfield won the silver medal in the 10m synchro event, while in the individual event Daley won silver and Waterfield the bronze. Three weeks later, in the Moscow event, Daley won silver in the individual platform event, while the pairing finished fifth in the synchro. In the final DWS meet of the year, in Tijuana, Mexico, Daley won gold in the individual platform event, and the pairing with Waterfield won bronze in the synchro event, although the Chinese did not compete in these events at this meet. Over the whole 2012 Diving World Series, Daley and the Daley/Waterfield pairing won both the overall individual and synchro 10-metre competitions.

In April 2012, Daley won the British elite juniors 10-metre platform title by a margin of 140 points at the Plymouth Life Centre.

In May 2012, Daley regained the European 10-metre platform title when he won gold at the Eindhoven championships with a score of 565.05 points, 49.65 ahead of Victor Minibaev in silver position.

In the British Gas Diving Championships held in Sheffield in June 2012, which were also the Olympic trials, Daley and Waterfield won the 10m synchro platform title with a new British record score of 475.77, more than 140 points ahead of silver medallists Daniel Goodfellow and Ross Haslam on 333.72. In the individual 10m championship, Daley regained the title for the first time since 2009 with a score of 547.60, ahead of Peter Waterfield on 452.80 and James Denny on 390.20.

At the 19th FINA World Junior Diving Championships, held in October 2012 in Adelaide, Australia, Daley lead a strong British team and rather unexpectedly won the Boys “A” 3m synchronised springboard competition together with Jack Laugher, who had won the individual 3m competition, they had had little practice together. Daley and Laugher scored 338.85 points, over 30 points ahead of Ilia Kuzmin and Maxim Popkov.

In January 2013, Daley was involved in the ITV celebrity diving show Splash!, where he was an expert adviser to the celebrity contestants. While the show got a largely negative critical response, it nevertheless got the largest ratings on each of the five Saturday nights it was broadcast, and was renewed for a second season in 2014. Daley was warned by British Swimming chief executive David Sparkes that taking part in the series would risk damaging his chances of winning an Olympic gold medal in the future.

Daley’s participation in competitive diving in 2013 was seriously restricted by an injury in May. In April he won the 10m competition at the Edinburgh leg of the Diving World Series, but while subsequently training for the Diving Grand Prix event at Fort Lauderdale, Florida, Daley injured his elbow and was forced to withdraw from the Fort Lauderdale competition and the subsequent DWS event in Mexico. In training for the 2013 World Championships, in Barcelona, Daley suffered a torn triceps for the third time, and only competed following intense medical attention and painkilling injections; he finished the individual 10m competition in 6th place.

In January 2014 Daley was involved in the second series of Splash!. Ratings were not as good as the first season, and the show was cancelled.

In 2014 Daley hosted a six-part travel series for ITV2 called Tom Daley Goes Global.

At the 2014 Commonwealth Games in Glasgow, Daley won a silver medal in the men’s synchronised 10m platform with diving partner James Denny and gold in the men’s 10m platform, with 516.55 points, retaining his title from the Commonwealth Games in Delhi in 2010.

In August 2014 at the European Championships in Berlin, the Daley/Denny partnership finished fourth in the 10m platform synchro competition, in only their second competition, while Daley won the silver medal in the 10m platform competition, with 535.45 points, behind Russia’s Viktor Minibaev who had 586.10 points.

In August 2014, Daley was one of 200 public figures who were signatories to a letter to The Guardian opposing Scottish independence in the run-up to September’s referendum on that issue.

For the 2015 season, Daley dropped the “demon dive” (backward 2.5 somersault with 2.5 twists, piked) which he had experienced difficulty with for several years, and replaced it with a forward 3.5 somersaults with one twist, which he called his “firework” dive and displayed for the first time at the British championships in Plymouth in February.

Daley announced his engagement to Black on 1 October 2015. Daley and Black married at Bovey Castle in Devon on 6 May 2017. On 14 February 2018, Daley announced via his Instagram account that he and his husband were expecting their first child through surrogacy, which caused some criticism due to the ethical issues surrounding surrogacy. Their son, Robert “Robbie” Ray Black-Daley, was born on 27 June 2018. The family live in London. Daley and Black do not share pictures with their son’s face online or on social media accounts.

In 2015, he became a patron of LGBT+ charity Switchboard (UK) and collaborated with YouTuber Calum McSwiggan to relaunch the charity under their new name.

For the 2016 season Daley was paired with Daniel Goodfellow for the 10m men’s platform synchro competition, with a view to competing in the 2016 Rio Summer Olympics in this sport.

At the 2016 Summer Olympics, Daley and Goodfellow won a bronze medal in the synchronized 10m platform. In the individual 10m platform, Daley placed first in the preliminaries (with an Olympic record score of 571.85 points, which was later broken by Chen Aisen in the finals). However, he had difficulties the next day, placing 18th in the semi-finals and failing to qualify for the finals.

In the 2017 FINA World Series, Daley has taken home 1 bronze medal in Beijing (10m Platform), 3 bronze medals in Kazan (10m Platform, 10m Synchro, and 3m Mixed), and one silver medal in Guangzhou (10m Platform). On 22 July 2017 he won the gold medal in the 10m platform event at the FINA World Championships held in Budapest.

In October 2017, Daley hosted the Virgin Holidays Attitude Awards for the first time.

In the 2018 FINA Diving World Series, Daley has won 1 silver medal and 1 bronze medal in Beijing (3m Mixed and 10m Synchro), 1 silver medal in Fuji (3m Mixed), 1 silver medal in Montreal (3m Mixed), and 1 silver medal in Kazan (3m Mixed).

At the 2018 Commonwealth Games held at the Gold Coast, Australia, Daley and Goodfellow won gold on the men’s synchronised 10-metres platform.

Daley partnered with Matty Lee starting in October 2018 in the men’s synchronised 10-metres platform. At the 2019 World Aquatics Championships held in Gwangju, South Korea, Daley and Lee finished in the bronze position in the 10m synchro.

On 30 September 2018, he was the guest on BBC Radio 4’s Desert Island Discs. His favourite choice was “How Long Will I Love You” by Ellie Goulding. His book choice was Harry Potter and the Philosopher’s Stone by J. K. Rowling and his luxury item was an oven.