"[Brown] had every opportunity to disengage from this situation and chose not to," Turnbull said.
The sentence was part of a plea agreement that resulted in Brown .
Baltimore County State's Attorney Scott Shellenberger said prosecutors felt it was important Brown "receive significant time in jail."
Brown, 19, and a 14-year-old girl were arrested and charged in the April 18 attack on Chrissy Polis, a transgendered woman. A county , charging her with assault and hate crimes.
Brown was also indicted on charges involving Vicky Thoms, the 55-year-old Rosedale resident who tried to stop the attack.
Rachel Cogan, a county assistant state's attorney, said the video showed "just how vicious and just how brutal" the attack was.
"It wasn't really a fight," Cogan said during the sentencing hearing.
Supporters of Polis rallied outside the fast-food restaurant on Kenwood Avenue in the days after the attack. Some gay, lesbian and transgender activists expressed concern about the initial absence of related hate crime charges against Brown.
Shellenberger said Tuesday that Brown's prosecution was not politically motivated.
"This isn't a political statement," Shellenberger said. "This is about prosecuting someone for a heinous crime that they committed."
Thoms did not speak during the hearing but spoke with reporters outside the Circuit Court building.
"I guess it was a fair sentence," Thoms said outside after the hearing. "I just wish there was more love in this world than hate."
Thoms said she still struggles with the attack.
"I never dreamed that I would see something like that, ever," Thoms said.
Polis, who wasn't present in court Tuesday, submitted a written victim impact statement. In that statement, she said she suffers from post-traumatic stress disorder and seizures as a result of the attack.
"I cannot go anywhere without the fear of getting hurt again," Polis wrote in her statement. "I want to go into a hole and hide."
Brown could be seen crying during her statement to Turnbull.
"That was not me," Brown said. "My mother did not raise me like that."
"I just want another chance," Brown said. "You won't see me no more ever again."