Police arrested Lance Cpl. Lewis Serna, Lance Cpl. John O'Leary, Pfc. Thomas Pentek and Pfc. Sean Miller Monday morning in connection with the incident, which occurred about 2 a.m. the same day, the Los Angeles Times reported Wednesday.
Witness Daniel Nunciato, 22, said he saw at least 12 men involved in the fight and heard one man in a blue football jersey shout anti-gay remarks while attacking the victim.
"He was choking him out on the ground, screaming ... 'You want to die?' " Nunciato said. "They were just stomping him there."
"Some of them were swinging and some of them were trying to pull the other guys off," he added.
Military spokesman Maj. Manuel Delarosa said the Marine Corps is cooperating with the Long Beach police investigation of the incident.
"This is behavior that's not acceptable in the Marine Corps," Delarosa said. "Any crimes of intolerance are unacceptable."
The four Marines were released from jail on bail and returned to their units at Camp Pendleton, the Times reported. The alleged victim's name and condition was not reported.