T. R. Knight

Theodore Raymond Knight was born on March 26, 1973, in Minneapolis, Minnesota. He began his connection to professional theater at age twelve through the Guthrie Theater in Minneapolis. Knight attended Annunciation Catholic School for grades K through 8 and later completed high school at the Academy of Holy Angels in Richfield. He received the Conners Foundation Scholarship as a freshman and apprenticed at the Children's Theatre Company. After a brief enrollment at the University of St. Thomas, he left school and returned to the Guthrie Theater, where he took on leading roles before eventually relocating to New York City.

Knight's early regional work in Minneapolis spanned multiple institutions. At the Guthrie Theater, his credits ranged from A Christmas Carol, in which he played Tiny Tim and later Dick Wilkins, to productions of A Midsummer Night's Dream, Ah, Wilderness!, and Amadeus, in which he portrayed Wolfgang Amadeus Mozart. He also appeared at the Jungle Theater in Journey's End, at the Minnesota History Theatre in Civil Ceremony, and at Chanhassen Dinner Theatres in Brighton Beach Memoirs.

His Broadway career began in 2001 with the revival of Noises Off, in which he played Tim Allgood opposite Patti LuPone. Two years later he appeared on Broadway in the 2003 revival of Tartuffe as Damis. That same year, his Off-Broadway performance in Scattergood, in which he played Brendan Hilliard, earned him a Drama Desk Award nomination for Outstanding Featured Actor in a Play. In 2004 he starred as the title character in the Off-Broadway drama Boy at Primary Stages. Knight returned to Broadway in 2010 in David Mamet's A Life in the Theatre, playing John opposite Patrick Stewart. His subsequent Broadway credits include It's Only a Play in 2015, in which he portrayed Frank Finger, and Stranger Things: The First Shadow in 2025, in which he played Victor Creel.

Beyond Broadway, Knight maintained an active Off-Broadway career that included productions of Marvin's Room, This Lime Tree Bower, Macbeth, The Marriage of Bette and Boo, Romeo and Juliet as Mercutio, and Pocatello at Playwrights Horizons, among others. In regional theater, he starred as Leo Frank in Parade at the Mark Taper Forum in Los Angeles, which opened on October 4, 2009.

Knight's most prominent screen role came in 2005 when he was cast as Dr. George O'Malley on the ABC medical drama Grey's Anatomy. The character was introduced as a surgical intern at the fictional Seattle Grace Hospital and advanced to the resident level over the course of the series, with his relationships to colleagues including Meredith Grey, Cristina Yang, Izzie Stevens, and Alex Karev serving as a recurring focus. Knight had anticipated only a single season when he auditioned for the role. He remained with the series through its fifth season, departing in 2009; he cited a breakdown in communication with executive producer Shonda Rhimes, reduced screen time for his character, and his decision to come out as gay as factors in his departure. He briefly reprised the role in 2020. His performance on the series earned him a nomination for Outstanding Supporting Actor in a Drama Series at the 59th Primetime Emmy Awards in 2007. Knight also appeared in the 2003 CBS series Charlie Lawrence alongside Nathan Lane and Laurie Metcalf, and in the 2016 limited series 11.22.63, in which he played Johnny Clayton, the abusive husband of James Franco's character's love interest. In 2019 he voiced Sir Cedric in the animated series The Bravest Knight.

Knight came out as gay in 2006 during his time on Grey's Anatomy. On October 7, 2013, he married Patrick B. Leahy, a ballet dancer and writer, in Hudson, New York.