Patrick Carter was driving to work and saw smoke from the burning house in the 4200 block of S. Elmgrove St., stopped, and knocked on the door to wake up three adults and three children who were sleeping inside.
The family got out without any apparent injuries.
"The mom had a look of shock on her face, and I said: 'You got to get out,'" said Carter, who said the family appeared to speak little English. "I'm happy, I'm happy for them. I just want to make sure they have a place to stay."
Seattle Fire got the call reporting flames and smoke coming from the two-story house at 9:21 a.m., said Seattle Fire spokesman Kyle Moore.
The fire apparently started in the basement and moved upstairs, Moore said.
Invesigators say the cause of the fire was accidental--caused by an electrical problem.
About $50,000 in damage was done to the structure of the home by the fire. The family lost $20,000 worth of belongings, fire officials said.
Meanwhile, American Red Cross is helping the family find temporary shelter.