Griswald is a bulldog who is sporadically seen in the show, often antagonizing Top Cat and his gang. He is vicious, but also gullible and dim-witted. He was once employed by the police to help Dibble with his beat. He is voiced by Don Messick in the TV series,
In the film, he starts out as an enemy of Top Cat, but is convinced by T.C. that he is, in fact, a cat, which Griswald believes due to his gullible nature. At the end, he is invited to stay with T.C. and become one of the gang. Griswald is voiced by Jason Harris in the UK version of the movie, and by Danny Trejo in the US release.