Officers responded to the scene, on Martin Luther King Jr. Way South near Walden Street, shortly after 8 p.m. after receiving a report of a serious hit-and-run accident involving a pedestrian, said Seattle police spokeswoman Renee Witt.
Arriving at the scene, police and medics found a 15-year-old boy in the street with a life-threatening head injury. He was rushed to Harborview Medical Center.
A preliminary investigation found that the 15-year-old and his brother were crossing Martin Luther King Jr. Way on the south side of the intersection with S. Walden Street when he was struck by a southbound car.
The car, described as a dark gray or charcoal Honda, kept going south after the crash without stopping to provide information or render aid, Witt said.
Police say the car should have a missing driver's side mirror, a broken front headlight assembly and possibly other damage.
Anyone with information about the car or driver is asked to call 911. Anonymous tips are welcome.