The former head of the Chicago Police Department, who was fired in December after an outcry over video footage of an officer fatally shooting a white teenager, said this week that he had limited power in that case.

In his first public remarks since Mayor Rahm Emanuel (D) asked for his resignation, Garry F. McCarthy said that despite what he called his limited involvement, he was forced out as protests mounted in Chicago.

“One of the things that people love to say to me in Chicago, they say, ‘Man, you got screwed, but somebody had to take the hit,’ ” he said during a discussion at Harvard University’s Kennedy School of Government on Tuesday. “I said, you’re right.”

McCarthy said the only step he could take under state law was to strip the officer involved of his police authority, which he said he did immediately.

During the panel discussion, which was focused on policing communities and also included The Post’s Tom Jackman, McCarthy said he has received “universal support” from the people with whom he has spoken.

However, McCarthy also said that while it was not his call, he agreed that the video should have been kept under wraps while the investigation into the shooting was ongoing.

“As the mayor said in December, he appreciates Garry McCarthy’s service to our city and his work to improve safety in our neighborhoods,” Adam Collins, a spokesman for Emanuel, said in a statement Friday. “While it was time for a new direction at the Chicago Police Department, the mayor wishes him nothing but the best in the future.”

McCarthy moved to Chicago in 2011 to lead the city’s second-biggest local police force after a stint as police director in Newark and deputy commissioner of the New York Police Department. While in New York, McCarthy oversaw the CompStat system there, which has since been adopted widely to monitor crime data around the country.

During McCarthy’s time as Chicago’s top police officer, the city was struggling to confront a legacy of police abuse that went back for decades and seeking settlements with victims. There was also a rash of gun violence, with homicides topping 500 in his first year in office.

McCarthy has been an outspoken advocate for stronger gun laws, repeatedly tying the number of homicides in the city to illegal gun possession. Experts said that McCarthy brought to the job a deep knowledge of police work as well as an interest in violence-prevention reform programs aimed at building trust in the department.

However, late last year, city leaders and activists called for Emanuel to fire McCarthy during widespread protests after authorities released footage of a white police officer shooting a black teenager. In the video, released after the city resisted doing so for months, Jason Van Dyke is seen firing a series of shots at 17-year-old Laquan McDonald.

Before his firing, McCarthy said he had limited authority in the Van Dyke case, saying in an interview that he oversaw “training, policy and supervision.” Emanuel, meanwhile, remains a focus of distrust and derision in Chicago, as does Anita Alvarez, the Cook County state’s attorney preparing for the Democratic primary next week.

The Justice Department announced the week after McCarthy’s firing that it would investigate the police department’s use of force and accountability to determine whether it has violated the Constitution.