The 71-year-old Cherry was sentenced to life in prison for his alleged role in the attack on Birmingham's Sixteenth Street Baptist Church, which was then a main meeting place for activists involved in the civil rights movement.
The bomb detonated on a Sunday morning while children were preparing for a youth-led service on Sept. 15, 1963. Killed in the blast were 11-year-old Denise McNair and Cynthia Wesley, Carole Robertson and Addie Mae Collins, all aged 14.
The bombing came amid tension over an order to integrate local schools issued just days earlier.
Cherry, who has long maintained his innocence, was the last suspect to be tried in the case. Two other former Klansmen, Robert Chambliss and Thomas Blanton Jr., have also been convicted in the bombing. A fourth suspect in the case died and was never charged.
Asked by the judge if he had any comment, Cherry pointed at prosecutors and said: "This whole bunch lied all the way through this thing."
"I told the truth," he said. "I don't know why I'm going to jail for nothing."
Eunice Davis, the sister of victim Cynthia Wesley, walked out of the courtroom in tears, saying, "It's time, it's time," the Associated Press reported.
An FBI investigation in 1965 listed Cherry as a suspect, but he wasn't charged in the bombing until 2000.