He has written for American Dad!, Community,[1] and The Mindy Project, and part of the first Marvel Cinematic Universe Spider-Man trilogy (2017–2021).

McKenna was an uncredited writer on the 2004 film The Girl Next Door, having developed the screenplay with director Luke Greenfield.

He also co-wrote (along with his brother Matt McKenna) one of the most acclaimed episodes of American Dad!, "Rapture's Delight".

[4][5] Having worked with the Russo brothers on the sitcom Community, McKenna contributed to the script of Captain America: The Winter Soldier (2014) by writing jokes for the film.

[citation needed] In Feb 2024, McKenna joined the cast of General Hospital, portraying WSB agent Jack Brennan, replacing Charles Mesure in the role.