According to Jim/ Season 7

Jim is an abrasive but lovable suburban father. Much like his real life counterpart, Jim's character is noted as a fan of blues music, as well as the Chicago Bears, Chicago Cubs, Chicago Bulls, and the Chicago Blackhawks. Jim & Cheryl, also raise five children – Ruby, Gracie, Kyle, Jonathan and Gordon. Throughout its run, the family's surname has never been revealed. Jim often finds himself in messy situations and his laziness inclines him to search for alternative ways of doing things with less effort. While Cheryl's brother Andy might be Jim's best friend, her sister Dana frequently teams up with Cheryl against Jim.

Jim Belushi, Courtney Thorne-Smith