Anecdotes

In his autobiography, Neil Patrick Harris, said that Radnor's seriousness as a person made "How I Met Your Mother" work because it grounded the show, which otherwise would have been akin to "The Simpsons" as a live-action cartoon. Harris noted that when his real-life close friend Katy Perry, did a cameo appearance on the show, she introduced herself to Radnor, and after she went to rehearse her lines Radnor shocked Harris by asking "Who is that?" and then confirming he didn't know anything about the super-famous Perry.

Made his Broadway debut in 2002 in the stage version of Le lauréat (1967), starring opposite Kathleen Turner and Alicia Silverstone.

Attended Kenyon College with author John Green.

His favorite films include Breakfast Club (1985), Before Sunrise (1995), Before Sunset (2004), Tootsie (1982), La Vie des autres (2006) and Happiness (1998).

He is of mostly Ashkenazi Jewish descent, and also has Irish ancestry, from his paternal grandfather.

He has an M.F.A. in acting from NYU's Tisch School of the Arts.

Is allergic to dogs.

Is a very avid reader.

At age 30 in 2004 before their How I Met Your Mother (2005) days, both he and Neil Patrick Harris appeared fully naked onstage in Jon Robin Baitz's The Paris Letter, where they played lovers.

Attended Kenyon College, where he won the Paul Newman award from the theater department

Was class president of his high school.

Graduated from Bexley High School, class of 1992, and came back as a guest speaker for the 2008 graduating class.

Was Lindsay Price's boyfriend from August 2008 to late 2009. They first met when shooting Spoiler Alert (2007).

He has two sisters who live in southern and northern California.

He was an extra in the movie 200 Cigarettes (1999) where he appears for a few seconds at the entrance of a punk club (30th min 19th sec of the movie). He doesn't have a line.

Campaigned for Barack Obama, in his 2008 election and 2012 re-election bids (focusing on his home state of Ohio). Stated in an interview "I despise politics, but I really like President Obama.".

Sings Lyric Baritone.

Originally cast as the American lead in the pilot of the WB sitcom Off Centre, appartement 6D (2001). The role was eventually played by Eddie Kaye Thomas.