Ben-Antir began his theatrical career. One of his first roles was in 2011 when he starred in the critically acclaimed Gillian Slovo The Riots at the Tricycle Theater. Later in 2012, he played Dimitrios at A Midsummer Night’s Dream at Regent’s Park Open Air Theater.
Ben-Adir also played Borachio in the production of Much Ado About Nothing’s Mark Rylance at Old Vic in London in 2013, as well as at God’s Property at the Soho Theater.
In 2014, he played at the Bush Theater in London, in the play known as We Are Proud to present a presentation about the hero of Namibia, formerly known as Southwest Africa, by the German Sudwestafrika, Between 1884-1915.
In the British crime drama Adam Smith Trespass Against Us, Ben-Adir plays the character Sampson and also plays the character Sir Tristan “Wet Stick” in Guy Ritchie’s King Arthur: Legend of the Sword. Some of the other films that have appeared include: Vera and The OA, among many others.
In 2013, he played Borachio in the production of Mark Rylance Very Ado for nothing at Old Vic in London and also played The property of God at the Soho Theater.
In 2014, Ben-Adir starred in We Are Proud to present a presentation on the hero of Namibia, formerly known as Southwest Africa, by the German Sudwestafrika, between 1884–1915 at the Bush Theater in London. The work received positive reviews.
Ben-Adir plays Sampson in the British crime drama Adam Smith Trespass Against Us starring Michael Fassbender and Sir Tristan “Wet Stack” in Guy Ritchie’s King Arthur: Legend of the Sword.