The shooting was reported at 8:38 p.m. Tuesday after the 28-year-old victim allegedly kicked over several garbage cans in the 1100 block of Gilman Avenue, according to police.
When someone asked him to stop and go home, the victim allegedly walked to a house nearby, then came back to the person's house a few minutes later and began yelling and grabbing at his waistband, police said.
The 62-year-old father of the man being threatened then shot the victim once in the chest, and called police.
Officers arrived and found the injured victim, who had a gun in his waistband. He was taken to San Francisco General Hospital to be treated for his injuries, which are considered life-threatening, according to police.
Police took the shooter into custody but had not yet released his name this morning.
Anyone with information about the shooting is encouraged to call the Police Department's anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411.