David Gilbert grew up in a Jewish family in Brookline, Massachusetts, a suburb of Boston. Inspired in his teens by the Greensboro sit-ins and other events of the Civil Rights Movement, he joined the Congress of Racial Equality at age seventeen. He entered Columbia University in 1962. In March 1965 Gilbert founded the Independent Committee on Vietnam (ICV) at Columbia University. Later, in the same year, he co-founded the Columbia University Chapter of Students for a Democratic Society which merged with ICV in the Fall of 1966 even though there was already a chapter set in place that was formed in the early sixties. The SDS chapter founded by Gilbert became renowned. Students for a Democratic Society (SDS). He traveled regularly to Harlem while working as a tutor, and saw Malcolm X speak at Barnard College in February 1965, experiences he describes as formative. Gilbert was one of the known attendees, by the FBI, at the Flint War Council. Gilbert, Kathy Boudin and Judith Alice Clark formed the May 19 Communist Organization.

After graduating from Columbia University in June 1966, Gilbert spent most of his days and evenings during the fall of 1967 downtown attending grad school at the New School, building an SDS chapter there or attending meetings at the New York SDS Regional Office. In addition, Gilbert spent his spare-time studying Marx's Das Kapital book and writing New Left theoretical papers on imperialism and U.S. domestic consumption, consumerism and "the new working-class." As Columbia SDS grew during the Spring 1967 term, Gilbert returned to the Columbia campus to offer a "radical education counter-course" for Columbia SDS freshmen and sophomores in a lounge in Ferris Booth Hall. Known by the late 1960s primarily as a young theorist, publishing articles in New Left Notes and other movement publications, he went on to play an organizing role in the April—May 1968 Columbia student strike.On April 4, 1968 Gilbert had his first arrest after walking into a police riot where 6 officers were beating a kid. He could not just stand there and allow it to continue so police turned on him. His charge was assaulting a police officer(apparently the cop scraped his hand when he tried to hit Gilbert in the head with his baton). His lawyer advised him to take a plea bargain because going to trial would mean the word of six officers against his.He plea bargained for being guilty of disorderly conduct and was fined $50. During the Columbia strike, which began on April 23, 1968, as part of the strike team and since he was in good relations with some of the faculty, Gilbert was called in to be a negotiator. At the time of the strike he was a graduate student at the New School for Social Research. In October 1969, he headed up a Weather collective in Denver and was arrested twice. The first arrest was for when he was passing out leaflets at a mall and his comrades were inside setting off a smoke bomb. The second arrest was when he was charged with "assault with a deadly weapon" after arresting officers found a rock in his pocket.

In 1969 SDS split into different ideological factions and Weatherman emerged, its purpose being to build up armed struggle amidst young white Americans in support of the Black Panthers and other militant groups and also oppose the war in Vietnam via activities intended to "Bring the War Home". Gilbert joined this group in 1969 with his friend, Ted Gold, who later died in the March 1970 Greenwich Village townhouse explosion, along with fellow Weather members, Diana Oughton and Terry Robbins. The group became a clandestine operation, and the organization was renamed the Weather Underground. When Weather went underground, members often used money they already had or received from their family to fund their efforts. Gilbert cashed in his Israel bonds and half of that money went to supporting Weather and the other half was put into the Black Panther bail fund.

David Gilbert became a part of the Bay Area collective and they were living in a San Francisco apartment. He and another member were out working on another group's car in Spring of 1971 when they were approached by two men in suits claiming to be real estate agents. The 'suits' asked a few questions and then left, alerting Gilbert that there might be a problem. He suspected that these men were actually FBI agents looking for information. After several meetings within the group, they decided to stay put for awhile. After more suspicious men started inquiring into the activities of other members, they decided to travel north. They holed up in a motel in Portland on a rainy night and watched television. Although not on the group's coordinating committee (the Weather Bureau), Gilbert did act as a regional leader, spending at least some of these years in Colorado. The Weather Underground committed several small bombings directed towards governmental and business property and buildings. As support for the group began to wane on the left, the pace of actions lessened and some members of the Weather Underground resurfaced in late 1976 and early 1977. Gilbert resurfaced briefly in Denver, Colorado between 1977 and 1979. Denver is where he helped organize a Weather collective in October 1969. Before surfacing, he managed to get his criminal charges dropped so he did not face any legal penalties. Gilbert, however, did not think it was in the best interest of the movement for him to resurface. Most Weather members were not prosecuted or did not serve time in prison despite having been sought by the police for years; police misconduct was the cause of many charges eventually being thrown out of court (see: COINTELPRO). Gilbert opted to continue his life underground. Gilbert and his partner, Kathy Boudin, remained active even following the birth of their son, Chesa Boudin, in August 1980.

In the late 1970s or early 1980s Gilbert and other white activists took the name RATF (Revolutionary Armed Task Force), declaring their solidarity with the Black Liberation Army (BLA). On October 20, 1981, the RATF participated along with several members of the BLA in an attempt to rob a Brinks armored car at the Nanuet Mall, near Nyack, New York. While Gilbert and Boudin waited in a U-Haul truck in a nearby parking lot, armed BLA members took another vehicle to the mall, where a Brinks truck was making a delivery. They confronted the guards and a shoot out ensued, almost severing the arm of guard Joe Trombino and killing his co-worker, Peter Paige. The robbers then took $1.6 million in cash and sped off to transfer into the waiting U-Haul. The truck was soon stopped by a police roadblock. Gilbert and Boudin surrendered but when the officers tried to search the back of the vehicle BLA members emerged shooting. Two police officers, Waverly L. Brown and Edward J. O'Grady, died in the shootout. Gilbert fled the scene with other RATF and BLA members but was caught by police that day. He was tried, and sentenced in 1983 to 75 years for three counts of felony murder. His extremely long sentence for participating in this action (especially when compared to Kathy Boudin, whose guilty plea earned her 20-years-to-life, from which she was paroled on 20 August 2003 and released 17 September 2003) may be due to his decision not to participate in his trial, not recognizing the authority of the state to try him. Gilbert has admitted that his participating in the Brinks robbery was wrong and apologized for his role in the "tragic loss of life" on that day. He does not deny his role in the robbery and subsequent murders.

Gilbert co-founded an inmate peer education program on HIV and AIDS in the Auburn Correctional Facility in 1987, and a similar, more successful project in Great Meadows Prison in Comstock following his transfer there. He has published book reviews and essays in a number of small/independent newspapers and journals, some of which were collected into the anthology No Surrender: Writings from an Anti-Imperialist Political Prisoner (Abraham Guillen Press) in 2004. He has also published longer single pieces on the topics of misleading AIDS conspiracy theories and white working class political consciousness. The 2003 documentary The Weather Underground featured interview segments with Gilbert, raising his profile beyond those in the small political prisoner support network who have been following his progress since his incarceration. The DVD release of The Weather Underground features a longer interview with Gilbert as a bonus feature.

Gilbert has served time in numerous upstate New York prisons, and is currently incarcerated at the Clinton Correctional Facility in Dannemora, New York. He is not eligible for parole until October 13, 2056.

David Gilbert co-wrote the pamphlet U.S. Imperialism with David Loud. The pamphlet was used across the country as a study guide by SDSers.

Gilbert co-wrote an article entitled "Praxis and the New Left." It appeared in the first issue of Praxis on February 13, 1967. The article which was written by Gilbert, Bob Gottlieb, and Gerry Tenney was part of a longer position paper called the "Port Authority Statement"

There is a mini-biography on David Gilbert on page 312 of the book "Outlaws of America The Weather Underground and the Politics of Solidarity" written by Dan Berger.

In an article found in the Columbia Daily-Spectator on April 2, 1983 Bob Feldman wrote "Beyond Brinks: David Gilbert Talks About the Robbery, the Underground, the Struggle"

The initial draft of Prairie Fire was written by Bill Ayers and Gilbert was part of a small group who took part in the editing and rewriting of Prairie Fire.

In response to Prairie Fire's purpose Gilbert said, "We needed something to re-mobilize us, we needed to have an organization to fight imperialism."