The blaze in the 900 block of Murrieta Boulevard was reported shortly before 1 a.m., Livermore-Pleasanton Fire Chief Jim Miguel said.
The fire consumed two upstairs units and was under control by 1:25 a.m., he said. Damage to the apartment complex was estimated around $100,000, Miguel said.
The Red Cross has been called to assist 11 people, all adults, displaced by the fire found in the apartment complex's six units, according to Miguel.
A man was airlifted to a burn center for respiratory issues, second-degree burns to the face and third-degree burns to the hands, he said. The man, one of the 11 people displaced, had reportedly tried to extinguish the fire, Miguel said.
No other injuries were reported and the cause of the fire is under investigation, he said.