Don Hagarty is a minor character in IT. He is young homosexual man in Derry, Maine and the life partner of Adrian Mellon.

Before Adrian came into his life, Don was planning on leaving Derry, not just because of it's violent homophobic attitude but because of the evil presence that lives in the sewers under the town. Before Adrian leaves, the two attend a town fair and are harassed by 3 homophobic teens, Webby Garton, Steven Bishoff Dubay and Chris Unwin on the way home. After the teens throw Adrian over a bridge and continue to beating up Don, Officer Andrew Redemacher arrives to stop the fight. When Don and Chris witnesses Pennywise attacking Adrian under the bridge, they try to tell Officer Andrew, Webby and Steven, but they didn't see anything.

After Adrian's body was found and buried in the Derry Cemetery John and Steven were sent to prison, nobody mentions Pennywise at the trial and both Don and Chris leave Derry.