The incident began as the shooting victim and some of his friends were walking along a sidewalk outside a home in the 9200 block of 30th Avenue SW just after 2 a.m. Saturday, said Seattle police spokeswoman Renee Witt.
Some of the people in the home came outside and one of them began fighting with the victim out on the sidewalk.
One of the other people from the house was standing there with a handgun on his belt. The suspect grabbed the gun and shot the victim in the chest, Witt said.
The suspect then gave the gun back and drove off in his own car.
After police and medics arrived, the victim was taken to Harborview, where the doctors were able to stabilize him. His condition was not immediately available.
Officers learned the name of the suspect, and were able to find his address on Queen Anne. They went to his house and arrested him without incident. He was booked into King County jail for investigation of assault.
Police said it is unknown what sparked the fight between the victim and suspect or if they even knew one another before the incident.
The investigation continues.