Harry Dunn, 19, died in August 2019 after his motorcycle was in a collision with a car driven by Sacoolas near RAF Croughton, an air force base in the English county of Northamptonshire that is used by the U.S. military.
Sacoolas, who pleaded guilty in October, did not attend her sentencing at London's Old Bailey central criminal court, but appeared by videolink from the United States.
Prosecutor Duncan Atkinson said a witness at the scene of the crash had recounted how Harry repeatedly said "don't let me die".
He said Sacoolas had admitted at the scene that it was her fault and she had been on the wrong side of the road, later telling police officers that she had been driving on "the American side".
Sacoolas, whose husband worked as a U.S. intelligence officer at the base, left Britain shortly after the accident, claiming diplomatic immunity from criminal prosecution and the United States refused to extradite her.
The crash led to a diplomatic spat between London and Washington, with the British government backing the call for Sacoolas to be prosecuted.
Judge Bobbie Cheema-Grubb said Sacoolas's lawyers had told the court before the sentencing hearing that their client had been advised by the U.S. government not to attend in person as it "could place significant U.S. interests at risk".
She read out a statement from Sacoolas's U.S. lawyer which said: "The U.S. government does not in any way support Mrs Sacoolas appearing in person at this hearing. In fact, Mrs Sacoolas' U.S. government employer has advice her not to attend."
(Reporting by Sam Tobin; writing by Michael Holden, Editing by Kylie MacLellan)
