Zack Whedon (born August 14, 1979) is an American screenwriter ('Deadwood', 'Dr. Horrible's Sing-Along Blog' and 'Fringe') and Comic Book writer ('Dr. Horrible and Other Horrible Stories', 'Terminator: 2029 to 1984' and Firefly/serenity's 'The Shepherd's Tale').
He graduated in 2002 with a film degree from Wesleyan University where he served as president of the Eclectic Society. Zack is from a family of writers: he is the son of screenwriter Tom Whedon, grandson of screenwriter John Whedon, and the brother of screenwriter/musician Jed Whedon and producer/director/writer Joss Whedon.
His first professional work in television was as a production assistant on his brother Joss Whedon's series, 'Angel'.
He is best known for his work, alongside his brothers Joss Whedon and Jed Whedon, on the parody musical 'Dr. Horrible's Sing-Along Blog' which he co-created and co-wrote.