The fire was reported in the 1400 block of Stevenson Street about 6 a.m. and was later controlled by firefighters.
The firefighter was injured when he fell about 6 to 10 feet at the scene of the blaze, according to a fire dispatcher.
American Red Cross volunteers are working in collaboration with local agencies to assist the residents affected by the fire, including connecting them to local services. The agency has provided food, water, blankets and other support at a local service center.
The DeLessio Market and Bakery provided breakfast to those affected Thursday and the Salvation Army provided lunch.
The cause of the fire is under investigation.