Jasper is a World War II veteran. Jasper also tried to avoid the draft by disguising himself as a woman and staying in Springfield to play in the local women's baseball league, along with his friend Abe, who was also avoiding the war. He has been a substitute teacher who confiscated everything made of tin (according to Lisa) and got his beard caught in the pencil sharpener. He also preceded Reverend Lovejoy as minister at the Simpsons' church in Springfield. Jasper's father was a legal immigrant from Ireland and his mother was an illegal Mexican immigrant, who was deported when Jasper was 11. Jasper unsuccessfully auditioned for The Be Sharps by singing "Theme From A Summer Place".
It is implied that Jasper is slowly going blind. This ailment was once cured by a laser fired by a house's security protection equipment, but he was blinded again almost immediately. He accepted this very quickly: "Oh, well. Easy come, easy go." Despite the sight problem, Jasper is a light sleeper, and is still quick with his reflexes. When Abe Simpson tried to steal his dentures one night, Jasper turned on the light immediately and, with a gun aimed at Abe, foiled the nocturnal theft. Also, when everyone comes to watch the Itchy & Scratchy episode "The Beagle Has Landed", he looks down to Bart and asks "Hey, little girl, is this seat taken?", Bart replies angrily with "I'm not a little girl!! Are you blind?!", in which Jasper replies sadly with "Yes."
