William Jackson Harper

Harper made his New York theatre debut in the 2006 Vital Theatre Company production of Full Bloom, a play about teenagers coming to terms with their sexuality. In 2008 he performed in Manhattan Theatre Club's production of Lynn Nottage's play, Ruined, which won the 2009 Pulitzer Prize for Drama. From 2009 to 2011, he played Danny Rebus in the PBS series The Electric Company. In 2010 he appeared in the Public Theater's mobile unit production of Shakespeare's Measure for Measure, and in 2011 returned for Titus Andronicus, this time at the Anspacher Theater. He starred as Marty Boy in debut of The Total Bent, a musical composed by Stew and Heidi Rodewald, that premiered at The Public Theater in 2012. The show was later reworked around Ato Blankson-Wood. Harper made his Broadway debut in 2014 portraying Stokely Carmichael in the Robert Schenkkan play All the Way starring Bryan Cranston as President Lyndon B. Johnson. The play revolved around the passing of the Civil Rights Act of 1964. The production went on to win the Tony Award for Best Play. Harper and Carrie Coon co-starred together in the 2015 Melissa James Gibson play, Placebo at Playwrights Horizon Theater. Marilyn Stasio of Variety praised him writing, "Harper inhabits the difficult role as comfortably as someone who lives in robe and slippers". The following year he took a supporting role in the Jim Jarmusch drama Paterson (2016) starring Adam Driver.

In 2016, Harper was cast on the NBC comedy The Good Place created by Michael Schur. Before landing the role of Chidi Anagonye, he considered quitting acting. Harper did not learn about the show's real premise until after he was cast. His performance has received critical praise and he was nominated for the Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series in 2020. In 2017, in between filming the show's first and second seasons, he had a leading role alongside Cristin Milioti in Zoe Kazan's futuristic romantic drama After the Blast at Lincoln Center's Claire Tow Theatre. Also in 2017 he had a supporting role in the VH1 drama series The Breaks.

In 2018, Harper's play Travisville had its world premiere at Ensemble Studio Theatre. In an interview with Bloomberg News, he revealed that the play was inspired by the displacement of a poor Black community that was situated near the grounds of the Texas State Fair in Dallas. The same year, he appeared in the sci-fi film They Remain. In 2019, he starred in two critically acclaimed films, playing Josh in the Ari Aster directed horror film Midsommar and James Ross in the Todd Haynes legal thriller Dark Waters. Also that year, he voiced John Mercer Langston in season one of the Airship podcast 1865, which details the weeks immediately following the assassination of US President Abraham Lincoln.

It was announced in April 2020 that he would narrate the Marvel audio book series Black Panther: Sins of the King, and in November 2020, that he would star in season 2 of the HBO Max anthology series Love Life. In 2021 he acted in the Barry Jenkins directed Amazon Prime Video miniseries The Underground Railroad adapted from the Pulitzer Prize-winning 2016 historical novel of the same name by Colson Whitehead. For his performance Harper was nominated for the Critics' Choice Television Award for Best Supporting Actor in a Movie/Miniseries. In October 2022, it was revealed that Harper joined the cast of Ant-Man and the Wasp: Quantumania, set in the Marvel Cinematic Universe. The film was released in theaters on February 17, 2023.

In 2023 he starred as Kenneth in the Eboni Booth play Primary Trust at the Roundabout Theatre Company Off-Broadway. The play ran from May 4 to July 2 at the Laura Pels Theatre. For his performance Harper won the 2023 Obie Award for Outstanding Performance. Harper is set to return to Broadway playing Astrov in the 2024 revival of the Anton Chekhov play Uncle Vanya starring Steve Carell, Alison Pill, Jayne Houdyshell and Alfred Molina at Lincoln Center. For his performance he received a nomination for the Tony Award for Best Actor in a Play. In January 2026 it was announced that Harper was cast in Cry Wolf, a limited series on FX inspired by the Danish series Ulven Kommer.