In addition to writing for "Late Night", O'Malley has also written for "Joe Pera Talks with You", which he also co-starred in as Joe's neighbor Mike Melsky, and the 66th Primetime Emmy Awards. As an actor, O'Malley has been featured in several television shows, most notably "Detroiters", where he played Trevor, Tim's free-wheeling brother, and "Horace and Pete", where he played Eric, the boyfriend of Horace's daughter, played by Bryant. O'Malley has also appeared on "Broad City", and Netflix's "", and has been a recurring guest on "The Chris Gethard Show" since 2013. In 2019, he appeared on "I Think You Should Leave with Tim Robinson" and he appeared in 2021 on HBO's "That Damn Michael Che".