Fire broke out in the 3100 block of Lelia Court at 3:47 p.m., said Lt. Rick Janicki of the Marina Department of Public Safety.
Renfro's disabled step-grandmother, whose full name and age were not available, was taken to Community Hospital of the Monterey Peninsula as a precaution.
Renfro was playing video games in his room when he heard his name called.
A few minutes later he heard a commotion coming from his step-grandmother's room.
"I thought she was in trouble," Renfro said. "I opened the door and the room filled with smoke."
Renfro called out to the woman and found her sitting on the porch. He immediately put her in her motorized scooter and pushed her out to the street to avoid the explosion of several oxygen tanks in the house, Renfro said.
He soon ran back into the house to look for two of the family's six dogs but couldn't find them. Two dogs and a cat died in the fire.
"The smoke overcame me," Renfro said. "It happened so fast. The house was messed up."
Fire gutted most of the house and left gaping holes in the roof, and there was extensive smoke damage, firefighters said.
Neighbor Ed Sachs was taking out the trash when he saw flames coming out of the home and called for help.
Sachs said the flames shooting out of the roof were at least 10 feet high.
He said Renfro's quick action saved lives.
"He was a hero," Sachs said. "He was a good hero. He did a good job."
Janicki said the fire's cause is under investigation. A damage estimate was unavailable.
The Monterey County Chapter of the American Red Cross will be assisting the family of five with housing for several days.