Six fire engines and around 40 firefighters tackled a fire at a semi detached house on Stanstead Road in Catford.
Half of a three roomed flat on the ground floor was damaged by the fire. One man left the building before the Brigade arrived and was taken to hospital by London Ambulance Service.
Control Officers took the first of nine calls at 0538 and mobilised crews from Forest Hill, Lewisham, Greenwich and surrounding fire stations to the scene. The fire was under control by 0638.
The cause of the fire is under investigation.