Rusty Wells and his band are just about ready to leave Chicago for their annual spring break trip to Fort Lauderdale. That is, until Big Frank extends their stay at his club. Big Frank's daughter decides to go to Lauderdale with her friends for spring break, so he gets Rusty and his band to look after her and to make sure she stays out of trouble. While he attempts that, Rusty has to contend with a good-time girl, Deena, who has no patience for guys who stand her up or keep her waiting.
Although MGM presented Girl Happy as a beach party film ("Elvis brings his beat to the beach!" "Elvis jumps with the campus crowd to make the beach 'ball' bounce!") and while Presley had previously appeared shirtless in films prior to this, he never appears without a shirt at anytime throughout his many scenes at the pool and on the beach, even wearing long sleeves for most of the film.