Kathy Boudin was born on May 19, 1943, in Manhattan, New York City, into a highly intellectual and politically engaged Jewish family. Raised in Greenwich Village, she grew up in an environment of leftist activism and legal advocacy. Her father, Leonard Boudin, was a renowned civil liberties lawyer who represented high-profile clients such as Paul Robeson and the Cuban government. Her mother, Jean Roisman Boudin, was a poet, and her family lineage included figures such as Marxist theorist Louis B. Boudin and journalist I.F. Stone, Kathy's uncle by marriage.

A gifted student, Boudin graduated valedictorian from Bryn Mawr College in 1965. She briefly attended Case Western Reserve University School of Law before fully committing to radical political activism in the late 1960s. During this period, she became involved in the anti-war movement and later co-founded the Weather Underground Organization, a far-left militant group that splintered from the Students for a Democratic Society (SDS). The group believed in revolutionary tactics to combat systemic racism and U.S. imperialism, often through symbolic bombings of government institutions.

Boudin’s deepening involvement in radical politics led her to live underground for over a decade. In 1970, she survived the Greenwich Village townhouse explosion—a catastrophic incident in which several Weather Underground members died while constructing a bomb intended for a military dance. Following the explosion, she fled from law enforcement and remained a fugitive, continuing to engage in underground revolutionary activities, though no bombings she participated in during that period resulted in casualties.

By the late 1970s and early 1980s, Boudin had formed a personal and political partnership with fellow activist David Gilbert. In 1980, the couple had a son, Chesa Boudin, who would later become the District Attorney of San Francisco. Chesa was raised by fellow former Weather Underground members Bill Ayers and Bernardine Dohrn after his parents’ arrests in 1981. Kathy Boudin’s underground life culminated in her involvement in a violent armored car robbery in New York—a turning point that would alter her life and bring her revolutionary era to an end.

On October 20, 1981, Kathy Boudin participated in a deadly armed robbery of a Brink’s armored vehicle in Nanuet, New York, carried out by a coalition of former Weather Underground members, Black Liberation Army militants, and the May 19th Communist Organization. The operation targeted a cash transfer from the Nanuet Mall, resulting in the theft of approximately $1.6 million. Boudin's role involved acting as a decoy in the front passenger seat of a U-Haul truck used as a switch vehicle in the robbery. Her presence was designed to lull responding officers into believing the truck posed no threat.

When police officers Edward O'Grady and Waverly Brown from Nyack, New York, pulled over the suspicious vehicle, Boudin reportedly stepped out and attempted to reassure the officers. At that moment, armed accomplices hiding in the back of the truck emerged and opened fire. Officer Brown was killed instantly, and Officer O’Grady died shortly afterward from his wounds. Earlier during the heist, Brink’s security guard Peter Paige had been shot and killed, while his colleague Joseph Trombino was seriously wounded but survived. Two other police officers were also injured in the attack.

Boudin was arrested while attempting to flee the chaotic scene on foot. Though she did not fire a weapon, she was charged under the felony murder rule, which allows accomplices to be held criminally responsible for deaths that occur during the commission of a felony. In 1984, as part of a plea agreement that spared her from three consecutive 25-to-life murder sentences, she pleaded guilty to one count of felony murder and one count of first-degree robbery. She was sentenced to 20 years to life in prison.

During her incarceration at Bedford Hills Correctional Facility for Women, Boudin became a prominent voice for prison reform and inmate education. She earned a master's degree in adult education and co-founded the AIDS Committee for Education (ACE) to promote awareness and support for incarcerated women living with HIV/AIDS. She also published academic work and poetry, advocating for restorative justice and family-focused rehabilitation programs.

After serving nearly 23 years, Boudin was granted parole in August 2003 and released on September 18 of the same year. Post-incarceration, she worked in HIV/AIDS support and re-entry programs for formerly incarcerated individuals. She later became an adjunct professor at Columbia University’s School of Social Work and co-founded the Center for Justice at Columbia, which promotes alternatives to incarceration and supports criminal justice reform.

Kathy Boudin died on May 1, 2022, at the age of 78, following a battle with cancer. Though her criminal past remained controversial, her post-prison work was widely recognized for its impact on education, health care, and prison justice reform.