The fire started around 5:30 p.m. Sunday on the 6700 block of North Woodstock Street.
Before firefighters arrived, neighbor Andre Thompson said he alerted others and tried to get to the man inside the burning home.
Thompson said he had a hard time getting inside the home.
"We're kicking the door next door to get the people out and then I try to go back over there [to get the man out], but he was a hoarder, too much stuff in there, couldn't get him out," Thompson said.
Neighbors said the resident was an older man who lived alone and had his belongings lying all over the porch.
"He's a hoarder. I'm going to say a professional hoarder. As you can see in the front of his yard there's a whole bunch of stuff - a whole bunch of stuff on the porch," another neighbor said.
When firefighters arrived, they found smoke coming from the second floor.
It took more than 30 minutes to place the fire under control, officials said.
Crews found a lot of belongings inside the home, as well.
One person was rescued and was taken to an area hospital for treatment.
Due to the seriousness of injuries, the arson and explosives task force was called in to assist the fire marshal in the investigation.
Residents said they believe the person who lived inside did not have working utilities.
The cause of the fire remains under investigation.