Teonna Monae Brown had pleaded guilty last month to first-degree assault and a hate crime in the beating of Chrissy Lee Polis, 22, at the Rosedale McDonald's in April, The Baltimore Sun reported Tuesday.
The attack attracted national attention after an employee who videotaped it posted it online.
Baltimore County Circuit Court Judge John Grason Turnbull II called the attack "absolutely outrageous behavior" and said the prosecutors' sentencing recommendation, which he followed, was "more than reasonable."
The judge had watched the employee's videotape that showed Polis being kicked and struck in the head, then dragged by the hair across the floor, as well as a video from McDonald's surveillance footage.
Polis, who did not attend the sentencing, said in a written statement Brown and a 14-year-old who has admitted her role spat on her, called her names, kicked her and pulled out her hair.
"While being beaten, I felt like I was going to die that day," Polis wrote. She said she suffers post-traumatic stress disorder, has lost her job and fears being hurt again.
Some advocates for transgender people said the sentence was too lenient, the Sun reported.
Brown apologized and asked for probation.
Her lawyer, Timothy Knepp, called the penalty overly harsh for the first-time offender.