Ahmed's film career began in the Michael Winterbottom film The Road to Guantanamo, in which he played the part of Shafiq Rasul, a member of the Tipton Three.He and another actor involved in the film were detained at Luton Airport upon their return from the Berlin Film Festival where the film won a Silver Bear Award.Ahmed played a role in the Asian Dub Foundation opera Gaddafi and a starring role as psychotic serial-killer-turned-born-again-Christian Lucius in the Lighthouse Theatre's acclaimed production of Stephen Adly Guirgis's Jesus Hopped the 'A' Train (directed by Jack William Clift and Thomas Sweatman) as well as in Shan Khan's Prayer Room.
The British actor was attending a friend's wedding in Los Angeles, when his talent agent suggested he meet Gilroy to discuss the film's script.
Gilroy told Ahmed that he had seen his previous work; he was not fit for the role, but still allowed him to audition.
At the 2017 Emmy Awards, he received two nominations, for his performance in The Night Of and his guest role in Girls; he won the award for Outstanding Lead Actor in a Limited Series or Movie for the former, becoming the first South Asian male to win an acting Emmy, He went on to play Carlton Drake / Riot in the superhero film Venom (2018).
As a rapper, he is a member of the Swet Shop Boys, earned critical acclaim with the hip hop albums Microscope and Cashmere, and earned commercial success featuring in the Billboard 200 chart topping Hamilton Mixtape, with his song "Immigrants (We Get the Job Done)" winning an MTV Video Music Award.
He featured in the title role of the 2009 independent film Shifty, directed by Eran Creevy.