"We are grateful that the Parole Board has affirmed that anyone who has already interacted with Judy already knows that she is a rehabilitated, remorseful woman who poses no threat to society," said Clark's attorney Michael Cardozo.
The 69-year-old former radical activist was convicted in Nyack, New York, of a murder in which a security guard and two police officers were dead, according to court documents.
Clark took part in the crime with other activists and described himself as a "rampage fanatic … in the war with America" and "a blind revolutionary," according to the records of the New York State Department of Corrections.
She was initially sentenced to 75 years in prison, but the governor of New York, Andrew Cuomo, reversed her sentence in 201
"She talked about her grief, her complicity, and why she did it," Cuomo told reporters after personally interviewing Clark more than two years ago. "Overall, I thought it was very impressive."
Clark had previously been denied probation after a Board found that her release was "incompatible with the good of society" and "devalued the gravity of her crimes to undermine respect for the law," according to the Department of Corrections ,
The board also said Clark was still considered a "symbol of violent and terrorist crime."
CNN has contacted the New York State Department of Corrections and the Cuomo Office for comment.
Clark's lawyers handed over some 2,000 letters from state and local leaders and residents to the Probation Service, saying that they believe she has been rehabilitated and that she should be released.
Donna Lieberman, executive director of the New York Civil Liberties Union, expressed her support for the board's decision.
"Our corrective system does not exist to punish people, and the basic premise of our probation system is permissible for people to repair their lives," Lieberman said in a statement.
"Today, the Probation Commission has sent an important message to the entire country, showing that New York is justice, and recognizes that the detainees should be given the opportunity to return to society."
During her time at the Clark Prison, also known as Judith, she has trained law enforcement personnel, taught prenatal care, established an AIDS counseling program, and became a chaplain.
Clark is being held at Bedford Hills Prison in Bedford Hills. New York.