Career
Radnor was cast as the lead in The WB series Off Centre. However, the role was re-cast with Eddie Kaye Thomas before the first episode aired. In 2002, he made his Broadway debut in the stage version of The Graduate, succeeding Jason Biggs, opposite Kathleen Turner and Alicia Silverstone. In 2004, Radnor starred in The Paris Letter alongside his future How I Met Your Mother co-star Neil Patrick Harris. From 2005 to 2014, Radnor starred as Ted Mosby in the CBS sitcom How I Met Your Mother, his biggest role to date. The series ran for nine seasons and revolved around friends living in New York City and finding love. He acted alongside Cobie Smulders, Neil Patrick Harris, Jason Segel, and Alyson Hannigan.
In July 2008, he starred opposite Jennifer Westfeldt in the premiere of the play Finks, written by Joe Gilford and directed by Charlie Stratton for New York Stage and Film. Radnor made his directorial debut with the film Happythankyoumoreplease, where he was both the writer and star of the 2010 comedy-drama.
His second directorial effort, Liberal Arts, starring himself and Elizabeth Olsen, premiered at the Sundance Film Festival on January 22, 2012. Radnor appeared in the Broadway production of Disgraced, which opened October 23, 2014, at the Lyceum Theatre. He is set to direct the sci-fi thriller film The Leaves. From 2016 to 2017 he played Dr. Jedediah Foster in the historical medical drama Mercy Street on PBS.
In October 2016, Radnor also confirmed he is in a band, Radnor and Lee, with Australian musician Ben Lee. Radnor and Lee had known each other for "twelve or thirteen years after meeting on the set of How I Met Your Mother" eventually writing songs together. Their debut album, Radnor & Lee was released on November 10, 2017, "receiving widespread praise across the board, and cementing the duo as an accomplished pair of artists," stated Rolling Stone. On February 19, 2020, Spin announced Radnor and Lee's sophomore album, Golden State, out on Flower Moon Records, and premiered the first single "Outside In." American Songwriter later premiered the video for the album's 2nd single, "Simple Harmony." Due to the COVID-19 pandemic, the album's release date was pushed back to June 2020. Radnor's debut solo EP, One More Then I'll Let You Go, was released on April 16, 2021, on Flower Moon Records. Rolling Stone premiered the first single, "The High Road," March 10, 2021, calling it a "gently lilting ballad about the breakdown of a friendship on which he sings... which features deep textures of piano, acoustic guitar, organ, and snapping fingers." The EP's 2nd single, "You Feel New," premiered on March 31, 2021, with features in Rolling Stone, NPR, American Songwriter and Paste Magazine.
From 2020 to 2023, he starred as Lonny Flash in the Amazon Prime series Hunters, acting alongside Logan Lerman and Al Pacino. He voiced Durpleton in the Netflix animated series Centaurworld (2021). He took a recurring role as Adam one of the protagonists friends, in the FX on Hulu limited series Fleishman Is in Trouble (2022). He acted alongside Jesse Eisenberg, Lizzy Caplan, and Adam Brody. The series went on to receive a nomination for the Primetime Emmy Award for Outstanding Limited or Anthology Series. In 2024 Radnor returned to theatre starring in the Itamar Moses play The Ally directed by Lila Neugebauer at The Public Theater. In 2026, Radnor made his London theatre debut in Jonathan Caren's 2025 play, Hit Machine. The production received mixed reviews from critics, while Radnor's performance was generally praised.