Six fire engines and around 40 firefighters tackled a fire at a flat on Solon New Road in Clapham.
Most of a flat on the 11th floor of a 15-storey residential building was damaged by fire. One man was taken to hospital by London Ambulance Service crews suffering from smoke inhalation.
The Brigade's 999 Control Officers received 29 calls about the fire.
The Brigade was called at 1958 and the fire was brought under control by 2058. Crews from Clapham, Brixton, Battersea, Lambeth and Tooting fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and Metropolitan Police.