Acting career
Anderson played Angelo in the film 4.3.2.1. In 2011, he starred in the ITV drama series Injustice as Simon, a teenager in a youth offender institution. He also had a guest role on Outnumbered. He also appeared in an episode of Skins, and appeared in the feature film Comedown, co-starring Adulthood's Adam Deacon and directed by Kidulthood director Menhaj Huda. Anderson featured in various plays, including Dunsinane for the RSC, King Lear (with Pete Postlethwaite) at the Young Vic Theatre, and War Horse at the National Theatre. He was seen in the teen slasher film Demons Never Die, playing Ricky, and appeared in the BBC Two comedy Episodes, alongside Matt LeBlanc and Stephen Mangan.
In 2012, Anderson was cast for the third season of HBO's television series Game of Thrones as Grey Worm, the leader of Daenerys Targaryen's Unsullied army. Anderson continued to portray this role through season 4, season 5, season 6, season 7 and season 8. He played Dean Thomas, the boyfriend of Chloe Latimer, on the ITV drama Broadchurch in 2013. In July 2021, he was revealed to be joining the cast of Doctor Who for the 13th series. In August 2021, Anderson was cast as the titular vampire Louis de Pointe du Lac in the AMC television series Interview with the Vampire. His performance was widely praised by critics. In their 2024 best performance reviews, Jackson McHenry of Vulture gave Anderson's performance "immense credits" for grounding the series, while Daniel Canfield of Vanity Fair praised Anderson's ability to fully embrace "the majestic emotional range required" in his portrayal.