Harry is a cat who Garfield often encounters. Usually in the series, Harry is shown as Garfield's frenemy.
Harry is in many ways like Garfield, in that he is very badly behaved. Unlike Garfield, he does not seem to have quite as much morality.
Harry loves to eat birds, and on two occasions Garfield has had to save some bluebirds from being eaten by Harry. He has also been able to get jobs on occasion, including one with Dr. Whipple where he pretended to be well-behaved. It annoys Harry greatly that Garfield usually tries to foil his jobs unintentionally and provides some gaps of static in their friendship.
- Mother Garfield
- Agent X
- The Pet Show
- Glenda and Odessa
- It's a Cat's World (Parallel Universe version)
- Extreme Housebreaking
- It's a Cheese World
- Out on a Limb
- The Amazing Flying Dog (Cameo)
- Home for the Holidays
- Night of the Bunny Slippers
- Dog Days (Cameo)
- Black Cat Blues
- The Bluebird of Happiness
- Fido Food Feline
- Stealing Home
- The Mole Express
- Furry Tales
- Kind to Kittens (Cameo)
- It's About Time
- Muscle Mouse
- Where's Odie
- Problems, Problems, Problems
- Lion Queen
- Lion Queen: King of Cats (cameo)
- Glitter Gulch
- Against All Tides
- My Dog, the Cat
- Fraidy Cat
- Harry has Heterchromia and he is one of four characters with colored eyes instead of black pupils, the others being Catzilla and Siam and Tyham.
- When Harry says "Oh no!", repeatedly in It's a Cheese World, his voice gets deeper.
- In Mother Garfield, Harry doesn't eat lasagna, but in The Pet Show, he has a craving for lasagna.
- Harry mentioned himself that he was faster and stronger, which means in It's a Cheese World, he is able to kick Garfield in the sky in strength, He can also ride a skateboard. Also, he said he was able to jump out across the rooftops, this was only mentioned in Out on a Limb.
- On his first appearance, Garfield first introduces him as the black cat that lives two doors down but in later appearances his shown as an alley cat.
- However, in Home for the Holidays, Harry mentions that his hungry, to which Arlene tells him they will get food back at home, implying they are both house-cats (although Arlene has been established as an alley cat as well).
- In one episode, Garfield notes that Harry is a two-sided character.