Garfield's Grandfather (voiced by C. Lindsay Workman) is the maternal grandfather of Garfield, Raoul, Sly and Garfield's other cousins, and the father of Sonja, Arno, Barney, Berle, Bernie, Bob, Ed, Edna, Evelyn, Harry, Hubert, Leo, Morty, Nick, Rockliva, Patrick, Roy and two unnamed sons. In both the comic strip and TV special continuity, Garfield's maternal granddad is a sulky and ill-tempered cat who continued to live in the Italian restaurant (which is Garfield's birthplace).
His appearance is a gray furry looking cat. He is a mouser and is proud of it. He wants Garfield to become a mouser, but being the mouse lover that he is, Garfield refuses, saying "I'd rather swallow my pride than that mouse." This irritates Garfield's grandfather. He is a tough cat. In December 1984, he is living with Sonja in abandoned pasta factory when Garfield winds up there in the comic strip.
He appeared with Sonja in the TV special Garfield on the Town, which later became a basis for the December 1984 comic strip sequence. Garfield, having just gotten into a fight with Jon over how they should live together, goes on to prefer staying with his natural family. However, because Garfield re-introduced the fight between the Claws and his family, his granddad orders him to just return home, calling him "Lardball", after the same insult is used by the TV special's main antagonist, the purple-furred leader of the Claws. Sonja however goes on to assure Garfield not to mourn over his granddad's orders to leave claiming that leaving to return to his life with Jon is so much better that his family envies him for this.
Ancestor from possibly the opposite side of the family
In a stretch of 12 comics in November 1980 (excluding a Sunday), a different-looking Garfield's grandfather showed up in his house and told about things when he was young; then he left saying he would write Garfield letters. However, Garfield yelled "cats can't write" and his ancestor replied "now you're getting the picture". In those comics, he had gray hair, a slim body shape and seemed to have a personality like Garfield. Possibly, that cat was Garfield's paternal grandfather shown only in those comic strips.