(CNN) -- Less than nine months after she shoved her husband off a steep cliff just days into their marriage, a federal judge sentenced Jordan Linn Graham to 30 years in prison Thursday.
Graham, 22, pleaded guilty to second-degree murder in December, admitting to luring her new husband, Cody Johnson, to Glacier National Park and pushing him off a cliff.
"After providing several false statements to law enforcement officers and impeding the investigation by providing false information, Graham ultimately admitted pushing Cody from behind with both hands," prosecutors said in a statement Thursday.
Graham filed a motion to withdraw her guilty plea on Wednesday, arguing that prosecutors had negotiated the plea deal in bad faith by pushing the judge toward a harsher sentence despite agreeing to drop a first-degree murder charge.
Prosecutors denied that claim and argued that Graham was trying to delay sentencing.
U.S. District Judge Donald Molloy denied Graham's motion to withdraw her guilty plea at Thursday's hearing, accepting the plea deal and sentencing her to 365 months in prison.
The judge's ruling came after several members of Johnson's family asked the judge to sentence Graham to life in prison, CNN affiliate KPAX reported.
The sentencing comes months after Graham's surprise guilty plea in the middle of the high-profile murder trial.
"It was a reckless act," Graham told the judge in December. "I just pushed."
When Graham declared her guilt, the victim's mother in the gallery crumpled in her seat.
Another relative of Johnson, who was 25, threw her head back and cried, whispering "she said guilty." His friends held hands and appeared satisfied.
When the judge first asked what happened the day her husband was killed, Graham responded, "I wasn't thinking of where we were."
Then she spoke of a deadly argument at the park and how she had misgivings about the marriage.
"I wasn't really happy," she said.
Before her guilty plea, Graham's defense lawyers had argued that the death plunge was an accident resulting from an argument. Graham initially lied to police, they said, because she was afraid she wouldn't be allowed to explain what happened on the cliff's edge.
CNN's Michael Martinez, Kyung Lah and Catherine E. Shoichet contributed to this report.