CONCORD — Owen Labrie must report to jail a day after Christmas after a judge Tuesday denied his bid to avoid serving a year in jail for the sexual assault of a 15-year-old prep school classmate.

A jury found the Tunbridge, Vt., 23-year-old guilty of misdemeanor sexual assault charges and endangering the welfare of a child.

The graduate of the elite St. Paul’s School also was convicted of using a computer in 2015 to lure his underage victim for sex, an offense that requires him to register as a sex offender.

Lawyers for Labrie argued he served two months in jail for violating curfew in 2016 and that he had effectively been under house arrest for more than two years.

Merrimack County Superior Court Judge Larry Smukler denied the motion to amend the sentence but agreed to let Labrie self-report to jail on Dec. 26. State prosecutors had objected to that planned surrender.

A spokesman for the state’s leading anti-domestic violence group praised Smukler’s ruling.

“We’re pleased to see that Owen Labrie’s attempt to avoid accountability for sexually assaulting a minor was denied,” said Amanda Grady Sexton with the New Hampshire Coalition Against Domestic and Sexual Violence. “Labrie’s continuous efforts to evade jail time demonstrates a clear lack of understanding of the seriousness of sexual assault, and has further shown the incredible lengths that predators will go to when refusing to accept ‘no’ for an answer.”

In early November, the Supreme Court voted 3-0 to uphold Labrie’s misdemeanor convictions.

Last month, the Supreme Court also heard oral arguments on Labrie’s other appeal, which claims ineffective counsel during his high-profile trial.

Labrie’s attorney, Christopher Johnson, argued his client received ineffective counsel from his previous lawyers who failed to defend him on the use of his computer charge or present arguments to the jury to refute it.

The jury cleared Labrie of felony sexual assault charges but convicted him of three sexual assault misdemeanors, the endangering misdemeanor, and felony for use of a computer to entice a minor into sexual activity. His 12-month jail sentence was put on hold while his lawyer pursued the Supreme Court appeal of the conviction.

The victim in Labrie’s case, Chessy Prout, has written a best-selling book about her experiences.

During the trial, email and Facebook messages between Labrie and then fellow student Chessy Prout were used as evidence.