Fire officials tell Action News the 57- year-old male victim was transported to Crozer Hospital in Upland, Pennsylvania. He died on Saturday.
His name has not been released.
Firefighters were dispatched at 12:40 p.m. Friday to a report of a person trapped inside a burning home on the 1000 block of Providence Avenue in the Brandywine Estates neighborhood of Claymont.
Arriving firefighters reported heavy smoke and fire coming from the home and quickly struck a second alarm.
"There were all these firefighters and ambulances coming in," said Nick Bucci. "They cut the roof open and big black smoke billowed out."
Police say the man trapped inside was able to call 911 to report the blaze before he lost consciousness.
"He said he was trapped. We had him on the phone for a while," said Claymont Fire Chief Eric Haley.
But fire officials say they had difficulty finding the victim amid thick smoke and mounds of trash. They were eventually able to rescue him from a second story window.
"Normal landmarks of the home were not distinguishable because of storage conditions and hoarding in the house," said Chief Haley.
The cause and origin of the fire remain under investigation.