The incident began when the trooper pulled the suspect over on Highway 101 near Brinnon at about 7 p.m. Saturday.
The driver became violent, punching the trooper in the face and trying to stun him with a Taser.
A Good Samaritan was driving by, saw what was happening and pulled over to help. The suspect was then brought under control and taken into custody.
The trooper was taken to a nearby hospital and is expected to fully recover.