The fire at 739 North Mariposa Avenue was reported at 8:30 p.m. Thursday with heavy smoke showing from the structure.
It took several dozen firefighters 16 minutes to put out the fire.
The flames were contained to a second story room that the Los Angeles Fire Department described as having packrat conditions. The firemen also found the victim.
"He had been a little ill and had been in a convalescent home, but he said he didn't want to die there. He wanted to come back to the house and finish his days out here," said neighbor Matt Spero.
There were no smoke alarms or fire sprinklers inside the 98-year-old home.
The exact cause of the fire was under investigation.