The fire started around 9:30 a.m. in a building in the 700-block of West Buena near Clarendon Avenue.
Two residents were hospitalized for smoke inhalation and are said to be in fair condition. The firefighter had trouble breathing and was taken to the hospital as a precaution.
Smoke from the fire spread so fast, resident Sammie Redmond was forced to climb out his fifth-floor bedroom window and wait for help.
"I didn't know if I was going to jump to save my life or someone was going to come save me," said Redmond. "I went and knocked on the doors to get everybody out. Because I only had a pair of shorts on, I said let me slide some pants on and once I was ready to come back out I couldn't, the smoke came all in the house and I couldn't see anymore.
"It was a little scary. Five minutes in you couldn't see him anymore, but he came out and he was fine," said Jennifer Sheahan who shot video with her cell phone.
Firefighters arrived in time to raise a ladder and rescue Redmond. The blaze started in the top floor corner unit opposite from him.
Aaron McGonigal also lives on the fifth floor. He woke up when the woman from the unit where the fire started banged on his door looking for help.
"She said she fell asleep and when she woke up her mattress was on fire, so we got her down the stairs, took her down the stairwell," said McGonigal.
Fire officials say everyone else evacuated safely and the two-alarm blaze was under control in less than a half hour. Residents were briefly allowed inside to gather some of their things, but it's unclear when they'll be let back in.
"I just grabbed clothes and books and things," said resident Shawn Casey.