Harley works at Monsters Incorporated as a laugh collector. When he was a scarer, he was at the bottom of the Scarer's Leaderboard. He was also seen at Harryhausen's among the panicking public when Boo appeared.
Harley has orange and yellow skin, with two large feet, each with three toes on them. He has sharp teeth, a large mouth, brown eyes and no arms.
- The growl that Harley makes in his appearance at Harryhausen's is a sound effect taken from the 1994 video game Tekken when the character King is hit lightly.
- Harley's last name, Gerson, is a reference to Dan Gerson.