They will be replacing David Goodman and Chris Sheridan. These two will still be on the show as executive producers.
Hentemann came aboard Family Guy during its second season as a writer. Callaghan has been on board the show from the beginning. He started as a writers' assistant.
"Mark is part of the heart and soul of the series," offered Gary Newman, 20th Century Fox TV chairman. "He's taken on post-production duties for Seth (MacFarlane) that Seth has never let anyone else do. Seth now has the utmost confidence in Mark's ability to post-produce the show and cut it."
After seeing the show get canceled twice, Callaghan called it "especially rewarding" to watch the show "become a major franchise."