The home, on the corner of Princeton Avenue and 108th Street in West Roseland was fully engulfed by the time the call came in at around 6:40 a.m.
Upstairs, Marshall Lewis, who said he is a Cook County Sheriff's sergeant, heard his smoke alarm going off and rushed to get out and call 911.
He tried to save himself and his landlord, living downstairs.
CFD officials give update on fatal Roseland fire
"On my way out the house, I seen smoke, and I couldn't hardly breathe," Lewis said. "I just see fire blazing by her room, blazing. I couldn't do nothing."
The 54-year-old woman, fire officials said, was found in her room.
"They located the victim on the first floor in a bedroom in a bed," CFD Battalion Chief Barry Temple said.
The flames were so intense, it was hard to get to the victim inside.
"There was heavy fire when they first came in, so they hadn't knocked out a fire extinguished some of the fire before they could find her," Temple said.
The woman was pronounced dead. Her son came to the scene and was visibly upset over her death.
The cause of the fire is under investigation.