Sixty-year-old Bobby "B.J." Smith was earlier convicted of second-degree murder in the June 2011 shooting of 63-year-old Robert Fowler.
The Peninsula Daily News reports Smith felt Fowler had threatened him with a knife and was on the verge of harming his daughter, but a jury rejected his self-defense argument.
Deputy Prosecuting Attorney John Troberg said Smith fired two shots into Fowler's head as he lay on the floor, "almost like an execution."
Smith's daughter also had testified that she heard Fowler say, "I'm sorry, I'm sorry, please don't," before Smith fired the final shots, making the crime "even more egregious," Judge George L. Wood said.
Smith was sentenced to 10 years, 10 months in prison. He will get credit for about 27 months served in the Clallam County jail and must serve 36 months of community service upon his release.