Capoue was a French youth international, having earned caps at under-18, under-19, and under-21 level, serving as captain for a portion of his stint with the latter team.

Capoue was born in the commune of Niort in Deux-Sèvres, and began his career playing for hometown club Chamois Niortais.

While playing in a youth league match against Toulouse, Capoue drew the attention of the club's scouts who offered the player a one-week trial.

During the early portion of the 2007–08 season, he played on the club's Championnat de France Amateur team in the fourth division making eight appearances.

[8] For the 2008–09 season, Casanova paired the young defensive midfielder with former youth teammate Moussa Sissoko and new signing Étienne Didot, who arrived from Rennes.

[19] Capoue made his debut for Spurs on 18 August, replacing Mousa Dembélé in a 1–0 win away to Crystal Palace at Selhurst Park.

[21] Capoue began his second season partnering Nabil Bentaleb in midfield, but his performance dropped while the Algerian was injured, and Ryan Mason made a breakthrough.

[26] On 6 July 2015, Capoue joined newly promoted Watford for a club-record transfer fee, reported to be around £6.3 million, on a four-year contract.

[31] On 30 December 2020, Capoue signed a two-and-a-half-year contract with Spanish club Villarreal for an undisclosed fee, starting on 4 January 2021.

[32][33] Capoue was named the man of the match in Villarreal's victory over Manchester United in the 2021 UEFA Europa League Final on 26 May 2021.

[42][43] On 15 August 2012, Capoue made his debut for the French senior team in a friendly match against Uruguay, Didier Deschamps's first game as manager.