The crash was reported along Big Tujunga Canyon Road after a public worker saw a vehicle off a cliff shortly before 5 a.m. Monday.
Five men in their 20s were in the vehicle and one of them reportedly suffered head trauma after being ejected. The four others reportedly walked for four hours until rescuers located them.
The victim who was ejected was transported to a nearby hospital by helicopter. He was said to be in serious condition.