Police dispatch received several calls reporting a crash in the 700 block of Cement Hill Road at about 3:20 a.m., according to Fairfield police.
Arriving officers found a 1988 Chevrolet Celebrity that had struck a tree and burst into flames, police said.
Several citizens had gone to the scene of the crash and pulled the 22-year-old driver and his passenger out of the burning car.
The passenger, 21-year-old Fairfield resident Steve Mann, died from his injuries at the scene, according to the Solano County coroner's office.
The driver was seriously injured and taken to University of California at Davis Medical Center. He is expected to survive, police said.
Investigators believe the driver was likely under the influence of alcohol at the time of the crash, police said.
The incident remains under investigation by the Fairfield police traffic unit.