Superior Court Judge Shelly Torrealba rejected media requests to photograph Harris due to the pending identity issue. He wore jeans and a long-sleeved white T-shirt with a logo on the front.
Harris was arrested Thursday in Los Angeles, ending a weeklong manhunt that began after the Feb. 21 shooting and crash that killed three people and injured five others.
Authorities allege Harris was driving his black Range Rover SUV when he fired at least five shots into a Maserati sports car, killing Kenneth Wayne Cherry Jr., an aspiring rapper who called himself Kenny Clutch.
The two men had argued minutes earlier in a casino valet area, police said.
After Cherry was struck, the Maserati careened into the taxi that exploded in a spectacular fireball at Las Vegas Boulevard and Flamingo Road, one of the most famous neon-lit crossroads in Las Vegas.
Michael Boldon and his passenger were killed. A passenger in the Maserati was shot in the arm, and four people in four other vehicles were hurt, none seriously.
Law enforcement officers arrested Harris at an apartment in Studio City.
Harris is a convicted felon in South Carolina who shows fists full of money on Internet posts and boasts of a high-rolling lifestyle with prostitutes in Miami and Las Vegas.