Warren was married to the actor who plays Angela Martin, Angela Kinsey. He is also the brother of Paul Lieberstein. Warren's writing partner is Halsted Sullivan, and they have written seven episodes of The Office together. He also appeared in the episode "Goodbye, Michael" as Toby Flenderson's brother, Rory Flenderson.
Episodes written[]
- "Café Disco"
- "Koi Pond"
- "Whistleblower"
- "China"
- "After Hours"
- "Turf War"
- "Paper Airplane"