
He is co-creator of the character Grimjack with Timothy Truman, who originally appeared in a back up story in the First Comics title, Starslayer, before going on to appear in his own book, again published by First Comics in the mid 1980s. His first published works were stories about the character "Sargon, Mistress of War", who appeared the First Comics series Warp!, based on a series of plays by that same Chicago theatre company. Originally an actor in a Chicago theatre company, Ostrander moved into writing comics in 1983.

He is best known for his work on Suicide Squad, Grimjack and Star Wars: Legacy, series he helped create. John Ostrander is an American writer of comic books.
