The fire began just before 4 a.m. in the 3300-block of West Cullom Avenue in a vacant two-story apartment building under construction, Chicago police and fire officials said.
It was put out about 3:55 a.m., but a male firefighter was taken to Swedish Hospital after falling through the floor in the building.
He remained stable, CFD said. No one else was hurt, according to CPD.
RELATED: Albany Park fire guts Twisted Hippo brewpub, gym, apartment building; 1 injured
Fire crews remained on the scene after 4 a.m. to investigate the cause of the blaze.
The same fire company battled another fire in Albany Park Monday that gutted a popular brewery, gym and an apartment building.