Sean Noonan was the uncle of Pat Noonan, a father figure to Tommy Monaghan, and veteran of the Korean War. He became a hitman of some renown after the war, but eventually ended up with a job tending bar in the Cauldron section of Gotham City. He eventually won the bar in a poker game, and soon “Noonan’s Sleazy Bar” became the resident hang out for local hitmen.
He was regrettably killed when he was stabbed by a captured mob hitman he was guarding.