Owen Labrie, 20, who had been free on bail while appealing his conviction, traveled to Boston multiple times to visit his girlfriend outside his curfew restrictions, according to prosecutors.
He had been required to remain home with his mother in Vermont between 5 p.m. and 8 a.m.
Labrie was sentenced to a year in jail after his August conviction on five counts, including one felony, stemming from an encounter at the elite St. Paul's School in Concord in 2014. At the time of the assault, the accuser was 15 and Labrie was an 18-year-old senior.
Labrie's attorney admitted his client's violation but said Labrie was visiting Boston for educational pursuits.
"I don't know if you were going down to Boston to consult with somebody, to meet a girlfriend or to pursue educational opportunities," said Judge Larry Smukler of Merrimack County Superior Court in Concord, New Hampshire.
"What is troubling is that you took it upon yourself to construe as was stated in your pleading, the spirit of the bail order and not the letter, and you made that decision yourself."
Labrie will be on probation for three years after his release and undergo a psychosexual risk evaluation.
"I believe you are neither the angel ... or the devil that is portrayed by the state," Smukler told to Labrie at sentencing.
Authorities said the encounter was part of a school tradition called the "Senior Salute" in which seniors sought to have sexual encounters with younger students, though the school has denied that such a tradition exists.
Labrie was acquitted of the most serious counts of aggravated felonious sexual assault. But he was convicted of a felony: the use of an online service to seduce, solicit or entice a child under 16 in order to commit sexual assault.
His conviction requires him to register on a sex offender list.
Labrie testified during the trial that the encounter in an attic room at the school was consensual and that there was no intercourse.
He testified that items of clothing were removed, but that the two kept their underwear on. The accuser, now 16, testified that Labrie penetrated her with his fingers before raping her. The prosecutor argued that it was a carefully planned sexual assault.
The trial brought unwanted attention to the elite school
, the alma mater of Secretary of State John Kerry and half a dozen congressmen.