Two fire engines and 10 firefighters and officer were called to a fire at a block of flats in Hulverston Close in Sutton.
Part of a flat on the ground floor of the building was damaged by fire.
One man was rescued by firefighters wearing breathing apparatus and he was treated at the scene for smoke inhalation by London Ambulance Service crews.
The Brigade was called at 0118 and the fire was under control at 0205. Two fire engines from Sutton fire station attended the scene.
The cause of the fire is under investigation