Personailty and Interest
Griffin is similar to Luanne's other roommates; he is lazy, he acts like a snob and is extremely liberal. He accuses Luanne of being "Hitler", a "HouseNazi", among other derogatory titles.
Griffin is also an ironic hypocrite because he does not like rules. A perfect example being that he participates in cross country bicycle races/marathons, which have certain rules set in place.
Griffin also seems to not pay rent, instead; opting to choose to freeload off Luanne instead of obtaining a job. When Luanne bought groceries; Griffin eats all the food implying he is carbohydrate loading for an upcoming race.
Griffin gets his comeuppance at the end of the episode, after Luanne cuts off the utilities to force him and the other roommates to contribute to live comfortably.
He later gets further comeuppance at the hands of the Arlen VFW members; Cotton Hill, along with Topsy come to the house, unaware that the former owner Pops, who was a friend of theirs, has passed away. When Griffin calls them Nazis, this offends Cotton, who shoot back that Griffin will learn what Cotton did to actual Nazis in the Second World War. As a result, Griffin is beaten by Topsy and Cotton.