Garth Fitzgerald IV is a hunter who generally works alone, although he has teamed up with the Winchesters on three separate occasions and once with Bobby, on a Rugaru hunt (although he sometimes almost got killed because he isn't that great of a hunter ). Garth drives a Ford Ranchero with shovels in the back, in case he needs to dig up a grave on a hunt. Once he puts a spirit to rest, he says that the spirit has been "Garthed." When he drives, he sometimes plays the song Poison by Bell Biv DeVoe.

After stepping up to fill Bobby's role, Garth becomes more serious and confident, as well as more capable at his job. He also adopts several of Bobby's mannerisms. He's described by Dean as someone who "grows on you".

Garth likes sweet things and comics, gets drunk easily, and appreciates a hot bath after a hard day's hunting. He likes giving hugs. Some time after Sam and Dean first meet him, Garth began a relationship with a "special lady" who knows about his hunting and also has twins.