Multnomah County Circuit Judge Julie Frantz told Shane Stant at a Thursday hearing that the law does not allow an assault conviction to be expunged.
Kerrigan, who is from Massachusetts, had opposed the request, saying in a letter that to grant it "would send a message to others that such a crime can ultimately be swept under the rug."
Stant, 34, said he made the request because the Navy's special warfare unit will not accept anyone with a felony conviction.
Stant served 14 months in prison for the conspiracy involving skater Tonya Harding and her ex-husband when Harding was seeking the U.S. figure skating title and a spot on the 1994 Winter Olympics team.
The plot was aimed at disabling Kerrigan, Harding's chief competitor.
Stant struck Kerrigan with a police baton as she prepared to compete in the U.S. championships in Detroit, leaving Kerrigan crumpled on the floor, grabbing her knee and crying out, "Why? Why?" Kerrigan recovered from the injury and won the silver medal in the Olympics.
Stant, Harding's ex-husband Jeff Gillooly and two other men went to prison; Harding served probation.
This summer, his lawyer filed court papers asking for Stant's conviction to be set aside, saying Stant had lived a law-abiding life since leaving prison and needed a break to achieve his dream of joining the SEALs.
In court Thursday, Stant asked for the expungement so that "my case doesn't overshadow who I am as a person."
Prosecutors objected and presented a Nov. 25 letter from Kerrigan, who also opposed the request, saying she is still asked about the attack.
"To allow Mr. Stant to have this act removed from his record would be an insult not only to me but to the thousands of athletes that strive to live by the Olympic credo," she wrote. "At the same time, I believe that granting Mr. Stant's motion would send a message to others that such a crime can ultimately be swept under the rug."
Stant now lives in Southern California and said Thursday that he works in marketing, although he declined to give details.
It was unsung Oksana Baiul of Ukraine who collected the gold medal in 1994, edging out Kerrigan. Harding was eighth.