Joe is the ex-boyfriend of Corey Flood. He cheated on her with Minnie, another girl from their school, and wanted to break up with Minnie (supposedly) because she was going to college. He planned on getting back together with Corey, probably for sexual purposes, but she turned him down.
He sang at their graduation (possibly wearing nothing under his graduation robes) and reminded everyone to go to the party later that evening. It was at that party that he tried to get back with Corey.
Corey was in a lot of pain after Joe broke up with her, because he was her "...first love and her first sex..." and she never really got over him. She wrote over sixty songs about the pain of the break up.