Conscientious objectors, including poet Robert Lowell and civil rights activist James Peck, were housed there for refusing to enter the military draft in the early 1940s.

[2][3][4] Robert Henry Best served most of his life sentence at FCI Danbury after being convicted of treason in 1948 for making propaganda broadcasts for the Nazis during the war.

Screenwriter Ring Lardner Jr., a member of the Hollywood 10, a group of filmmakers who were charged with contempt of Congress in 1947 for refusing to answer questions regarding their alleged connections with the Communist Party USA, served nine months there.

[7] Orange Is the New Black: My Year in a Women's Prison writer Piper Kerman criticized the move in an op-ed in The New York Times.

[15] In July 2024, former White House chief strategist Steve Bannon began serving a four month prison sentence at the facility for a contempt of Congress conviction.

A comprehensive program of fuel control, additional fire detection and suppression equipment, and training and planning sessions have also been established, not only at FCI Danbury but throughout the rest of the federal prison system.

[18][19] In 2008, supervisory staff at FCI Danbury discovered that Correction Officer Michael Rudkin had been having consensual sexual relations with a female inmate.

An FBI and United States Department of Justice Office of the Inspector General (OIG) [20] investigation revealed that Rudkin had sexual encounters with other inmates as well.

[22] Rudkin was severely beaten at the United States Penitentiary, Terre Haute on August 23, 2021 and died the following day at the age of 56.

In season 6 of The Sopranos, the character John "Johnny Sacks" Sacramoni, the head of the New York mafia family (played by Vincent Curatola), was incarcerated at FCI Danbury.

In the 2023 series White House Plumbers, G. Gordon Liddy (played by Justin Theroux) is promised he’ll serve the prison sentence for his role in the Watergate break-ins at FCI Danbury.