James Renee White Jr., 21, was pronounced dead at the scene after the 1:15 am shooting, police said.
A report of a disturbance sent officers to the Infusion Lounge, a nightclub at the shopping and entertainment complex outside the Universal Studios tourist attraction.
The club was hosting a disc jockey contest when a fight broke out and spilled outside, DJ Phil told KCBS-TV.
"A lot of guys were rumbling and fighting and of course, you know, they start throwing bottles and this escalated and gunshots rang out," the disc jockey said.
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Four people suffered minor injuries while trying to escape in the panicked, fleeing crowd, authorities said. No officers were hurt.
The shooting was an isolated incident, Universal Studios said in a statement.
"As one of LA's most visited family destinations, CityWalk will continue to provide the most comprehensive security available," the company said.
"We are committed to the safety and security of our guests and are working closely with law enforcement as their investigation unfolds.