At international level, he made his senior debut for Algeria in 2016, and won the 2019 Africa Cup of Nations where he was named player of the tournament and assisted the winning goal in the final.

After starting his career with French club Arles,[3] Bennacer signed for Premier League side Arsenal in July 2015.

Already a regular on Stefano Pioli's side, Bennacer form generated much praise from Italian pundits, showing dominating performance against the likes of Inter and Napoli.

[19] On 19 March 2022, Bennacer scored a screamer from outside the box against Cagliari, helping his team to win 1–0 and stay on the top of league table.

[24] On 2 December 2023, Bennacer made his return to the pitch in a 3–1 home win against Frosinone, coming on as a substitute at the 79th minute of the game.

[29] Bennacer was called up on 11 January 2017 to Algeria's squad for the African Cup of Nations of 2017[30] to replace Saphir Taïder, who suffered an injury in training.

His main characteristics are his speed, vision, intelligence, composure, dribbling skills, passing, and technique; he is also known for his ability to transition from defence into attack.