The subject of this folksy love song is Chuck E. Weiss, who was good friends with Tom Waits. In 1977, Weiss was working as a dishwasher at the Troubadour in Los Angeles when Rickie Lee Jones
performed there. She and Waits became an item, and the three of them spent a lot of time together, often drinking and taking drugs.
One night, Waits got a call from Weiss, who explained that he was in Denver and had taken up with a girl (who happened to be his distant cousin). When he hung up the phone, Waits told Jones, "Chuck E.'s In Love," and she seized on the title.