Teddy Bryan had pleaded guilty last month to second-degree murder in the death of 22-year-old Jonathan Favro, who worked as a corrections officer at the Washington Corrections Center in Shelton.
The 18-year sentence was the maximum possible under state sentencing guidelines.
The two had argued over a girl at a party July 14 in Hoquiam. Bryan admitted earlier in Grays Harbor County Superior Court that he stabbed Favro, but said he did not intend to kill him.
After the stabbing, Favro drove off and crashed into a rock embankment, then ran away from the wreckage, only to succumb to his stabbing injuries in a nearby back alley.
Meanwhile, Bryan returned to his girlfriend's home to wash off the knife and change clothes, police said earlier.
An officer spotted the car's wreckage and discovered that the car's air bags had deployed, but no one was inside. He then spotted blood on the air bag and car door.
Additional officers from Hoquiam and Aberdeen responded to the area. While they were checking the area for possible victims, a woman contacted police and said she had received a call from her 16-year-old son who told her he was "going to do something terrible."
The woman directed police to Bryan's location, about a block away from the crash scene.
Officers spoke to Bryan, who admitted stabbing the driver and the driver had then sped off in the car, according to police. Officers then found Favro's body in the alley.
KXRO reports that as Bryan enters the prison system his first stop will be the Shelton center where Favro worked. The center determines where inmates will serve their time.