The shooting happened outside Nicola's, a topless club in the 900 block of South Gerhard Avenue, at about 12:15 a.m.
The trouble started when a patron, who apparently had too much to drink, refused to leave the club. Authorities say the man tried to run over a security guard with his car.
The security guard shot the man, who was taken to County-USC Medical Center.
He is said to be in stable condition and is expected to survive.
City News Service contributed to this report.