Police Chief Carol Cummings said Officer Mark Atterbury should have called off the pursuit earlier.
The discipline was reported by The Daily Herald after it sought the information through public records law.
The pursuit took place in May 2013, when Atterbury spotted a man driving a stolen pickup and pursued him for miles through Snohomish County at speeds of up to 95 mph. During the chase, the pickup hit the officer's patrol car and another car before heading north up Interstate 5.
The pickup eventually turned off I-5 at Everett, turning onto Evergreen Way and heading north, blasting through several red lights at high speed as the officer followed with emergency lights and sirens on.
At the intersection of Rucker and Pacific avenues in Everett, the stolen pickup collided with a car and killed its driver, Rachel Kamin, 40, a registered nurse who was on her way to work.
The driver of the stolen pickup, later identified as Joseph Strange, is charged with murder for the death and is facing trial in October.