Moynihan is currently a series regular on the upcoming NBC comedy series The Fall and Rise of Reggie Dinkins created by Tina Fey, Robert Carlock and Sam Means. He stars along with Tracy Morgan and Daniel Radcliffe.

Recent film credits include Netflix’s Unfrosted: The Pop Tart Story directed by Jerry Seinfeld, Paramount’s Imaginary Friends directed by John Krasinski, and You’re Cordially Invited, alongside Will Ferrell and Reese Witherspoon. He has a recurring role on CBS’ newest franchise series NCIS: Origins.

Previously Moynihan was in the cast of NBC's Mr. Mayor as “Jayden Kwapis”, the loveably unhip interim Director of Communications whose bumbling personality hides his street smarts and political instincts. He co-starred alongside Ted Danson and Holly Hunter. Moynihan's other television credits include Unbreakable Kimmy Schmidt, Documentary Now!, Drunk History, The Simpsons, Miracle Workers, Girls, Portlandia, and Me, Myself & I. His voiceover credits range from “Panda” on the Cartoon Network animated series We Bare Bears, to “Louie” on DuckTales, and “Orka” on Stars Wars Resistance, both for DisneyXD, as well as on film in Pixar's Inside Out, Monsters University and others. Most recently, he voices the role of “Jedi Bob” in LEGO Star Wars: Rebuild the Galaxy.

His all-improvised podcast 'Celebrity Sighting! with Jonathan Biting!,' features Moynihan as the always candid and always hammered Jonathan Biting talking to guests all about their celebrity encounters. Now playing on Stitcher.

Moynihan also penned a children's book, Not All Sheep Are Boring, published by Penguin Young Readers, and is out now in bookstores and Amazon.