Buck was born December 13, 1947 in Midland, Texas, the daughter of Louis Buck, an Episcopalian minister. Her mother was a nurse; both are deceased. The family was active in the civil rights movement; when Dr. Buck desegregated his congregation, crosses were burned on their lawn and he was removed as minister, although the congregation remained integrated. He became a veterinarian to support his family.

Buck attended the University of California at Berkeley and the University of Texas at Austin, graduating from New College of California while incarcerated. She subsequently earned a Master's degree in Poetics from New College.

At the University of Texas, Buck was involved in organizing against the Vietnam War, as well as anti-racist activities. She joined Students for a Democratic Society (SDS) and in 1967 moved to Chicago where she edited SDS' New Left Notes and attended an SDS teacher-organizer school. With other SDS women she helped to incorporate women's liberation into the organization's politics. She subsequently returned to San Francisco where she worked with Third World Newsreel in outreach in support of Native American and Palestinian sovereignty and against U.S. intervention in Iran and Vietnam and in solidarity with the Black liberation movement. With colleague Karen Ross, she explained their practice: "We stop people on the street, and confront them with our films. Involve them as participants. It has come to them during a walk down the street, they’ve stumbled upon it. They have been confronted. The decision to watch, to register disgust or interest is now theirs. To those inquisitive, we explain more."

In 1973 Buck was convicted on two counts of purchasing (otherwise legal) ammunition using false identification and sentenced to ten years in prison. In 1977 Buck was given a furlough from prison and went underground instead of returning.

In 1979, Joanne Chesimard also known as Assata Shakur, who had been convicted of killing a policeman, and a leading member of the Black Liberation Army (BLA), escaped from a New Jersey prison with help from a number of associates outside. In 1983 Buck was recaptured and convicted of participating in Shakur's escape.

Along with a number of BLA members and supporters, Buck was convicted of conspiracies to commit armed robbery in the Brinks robbery of 1981 in which a guard and two police officers and a guard were killed. She allegedly drove the getaway car as well as helping to obtain a safe house and weapons. During the investigation into the armed robbery and killings, investigators found weapons and papers in an apartment in East Orange, New Jersey rented by "Carol Durant", an alias of Buck.

Papers there led police to an address in Mount Vernon, New York, where they found bloody clothing and ammunition belonging to Buck. Earlier in 1981, Buck participated in a similar armed robbery of a Brinks truck in the Bronx, during which one of the guards was murdered.

In 1985, Buck and six others were convicted in the Resistance Conspiracy case, a series of bombings in protest of United States foreign policy in the Middle East and Central America.

The May 12, 1988 indictment described the goal of the conspiracy as being "to influence, change and protest policies and practices of the United States Government concerning various international and domestic matters through the use of violent and illegal means" and charged the seven with bombing the United States Capitol building, three military installations in the Washington D.C. area, and four sites in New York City. Warnings were called in and no one was injured. The Capitol was targeted in retaliation for recent U.S. military invasions of Grenada and Lebanon. The military sites bombed were the National War College at Fort McNair, the Washington Navy Yard Computer Center, and the Washington Navy Yard Officers Club. In New York City, the Staten Island Federal Building, the Israeli Aircraft Industries Building, the South African consulate, and the offices of the Patrolmen's Benevolent Association were bombed or targeted. Six of those charged in the case have since been released from prison and one was never captured.

While in prison, Buck contributed articles on women in prison, solitary confinement, political prisoners and related issues to Sojourners Magazine, Monthly Review , and other journals and anthologies.

She published her poetry in journals, anthologies, a chapbook, and an audio CD. She received a PEN American Center prize for poetry in 2001. Her poems appeared in the anthologies Hauling Up the Morning, Wall Tappings, Igniting a Revolution: Voices in Defense of the Earth, Seeds of Fire, and in her chapbook, Rescue the Word. Her poems appear on the audio CD Wild Poppies (Freedom Archives 2004).

Her translations and introduction to Cristina Peri Rossi's poetry appeared in State of Exile, Number 58 in the City Lights Pocket Poets Series.

She died at home in Brooklyn on August 3, 2010, after a long battle with uterine cancer.