He is a member of the T-Birds, the coolest gang in Rydell High, and is Sandy's love interest.
Kenickie is known for his tough-guy image, rebellious nature, and deeply rooted sense of loyalty to his friends. He is also portrayed as somewhat insecure and desperately wanting to be "cool", which leads to some of his more questionable actions.
He ultimately develops a genuine affection for Sandy and changes his ways in order to be with her.