Developed at Paris Saint-Germain and Fulham, Dembélé made his professional debut for Fulham in the Premier League in November 2013, and totalled 19 goals in 64 competitive matches for them before joining Celtic in 2016. Dembélé helped Celtic win consecutive Scottish domestic trebles, before moving to Lyon in August 2018.
Dembélé has earned over 50 caps for France at youth level, and in October 2016, was called-up to the under-21 team.
In 2012, Dembélé signed for Fulham at age 16 from Paris Saint-Germain. He subsequently became a regular in the Fulham under-18 team and won the Premier Academy League in his first season with the club. He signed his first contract with Fulham in July 2013, lasting until the summer of 2015.
On 28 October 2014, in the fourth round of the League Cup, Dembélé scored his first professional goals, a brace which put Fulham 2–0 up at home against Derby County. However, the match ended in a 5-2 defeat.
Dembélé scored his first league goal for Fulham in a 2–1 win against Blackburn Rovers on 13 September 2015, and scored a brace in a 4–2 win against Reading on 24 October as Fulham overcame a 2-0 deficit to win 4–2. Dembélé scored twice again in the following match a week later as Fulham beat Bristol City 4–1 at Ashton Gate. By the end of the calendar year, he had totalled ten goals for the season.
On 3 August, Dembélé scored his first goal for the club with a 92nd-minute penalty against Astana (after having won the penalty himself) to put Celtic into the Champions League play-offs. He followed this up by scoring twice against Motherwell in the Scottish League Cup last 16 on 10 August, as Celtic ran out 5–0 winners. He also scored the fourth goal in a 5–2 win over Hapoel Be'er Sheva the following week.
On 10 September, as his club defeated Rangers 5–1 at Parkhead, he scored Celtic's first Old Firm derby league hat-trick since Stevie Chalmers in 1966, and the first Celtic player to score a hat-trick in any game against Rangers since Harry Hood in 1973. It was also considered to be a "perfect hat-trick", given his goals were scored with his head, his right foot and his left foot. On 24 September, Dembélé scored twice in a 6–1 win over Kilmarnock, then four days later, he scored his first two Champions League group stage goals against Manchester City, as Celtic finished the match with a 3–3 draw. His goalscoring form at that time saw him named the Premiership Player of the Month for September.
Dembélé scored a late winner in a 1–0 victory over Rangers on 23 October, sending Celtic to the League Cup final, and scored again in the final against Aberdeen, scoring from the penalty spot as Celtic won 3–0 for his first senior honour.
Dembélé was linked with a move to Chelsea during the January 2017 transfer window. Coincidentally, he was sent to a hospital in Chelsea for medical treatment on 31 January, the final day of the transfer window. However, Chelsea manager Antonio Conte dismissed the rumours, stating that he had never spoke to his board about Dembèlè. Later that day, Dembélé confirmed he was staying by tweeting a picture of himself celebrating a goal above an image of Leonardo DiCaprio's character Jordan Belfort from the film The Wolf of Wall Street.
Dembélé scored back-to-back hat-tricks in February 2017, in 5–2 and 6–0 victories over St Johnstone in the Scottish Premiership and Inverness Caledonian Thistle in the Scottish Cup, respectively with his final goal in the 5–2 victory over St Johnstone awarding him Scotland's 'Goal of the Season' for 2016–17 as well as the goal being nominated for the prestigious FIFA Puskas Award. The goal had 25 passes, a Rabona and a back heel, with every player getting a touch on the ball and a clinical finish at the end which completed Dembélé's hat-trick.
Throughout the 2017–18 Scottish Premiership season, Dembélé suffered three injuries keeping him out of action for a total of 82 days. Due to the injuries, Dembélé struggled to find the form of his 2016–17 Scottish Premiership season but still managed 16 goals in 39 appearances contributing greatly to Celtic completing their second consecutive domestic treble.
On 31 August 2018, Dembélé signed for Ligue 1 club Lyon on a five-year contract. The transfer fee was reported as €22 million (£19.7 million). He made his competitive debut for the club on 15 September in the 2–2 Ligue 1 draw at Caen, playing the full 90 minutes. On 26 September, Dembélé scored his first competitive goals for the club when he scored two first-half goals in the 3-0 Ligue 1 away win over Dijon.On 3 February 2019, he headed in the equalizer and later won the penalty which Nabil Fekir converted in the 2-1 Ligue 1 home win over Paris Saint-Germain and handed the Ligue 1 leaders their first 2018-19 Ligue 1 defeat.
Dembélé was part of the France under-19 squad which reached the semi-finals of the 2015 European Championship, scoring in group stage victories over Ukraine and hosts Greece. He made his debut for the under-21 team in October 2016, coming on as a second-half substitute and scoring one of France's goals in a 5–1 win over Georgia. On 13 November 2017, Dembélé scored an 11-minute hat-trick for the France U-21 team in a 3-1 away win over Slovenia, which was the forward's 7th goal in 10 games for the international outfit at the time. The hat-trick was also the quickest treble by a player in any French age group for 15 years.
As of match played 22 January 2019
Appearances and goals by club, season and competition