U.S. District Judge Kimberly J. Mueller approved the release of 20 minutes of testimony, which Ford gave Nov. 1, 1975, at the request of Sacramento defense attorney John Virga and which was played for jurors during Fromme's trial, the Sacramento Bee reported Monday.
Fromme, also known as "Squeaky," was a follower of cult leader and mass murderer Charles Manson, whose followers also slaughtered actress Sharon Tate and several of her friends, as well as supermarket executive Leno LaBianca and his wife Rosemary. She was convicted of attempting to assassinate Ford on Sept. 5, 1975, and sentenced to life in prison.
The tape, of which three copies were made, was later sealed and disappeared from public view.
Trial Judge Thomas J. MacBride originally ordered the copies to ensure at least two were usable for trial, the Bee said. Once that was determined, one tape was destroyed, a second was given to the president's legal counsel and the third was played at trial and then sealed.
Prosecutor Don Heller told the Bee he thought the intent was to destroy the tape after Fromme's trial but it remained in the court's possession. In 1987, MacBride ordered it unsealed but restricted its viewing and copying.
The videotape's release came from a motion filed last month by the Eastern District Historical Society, a non-profit agency that preserves the history of the federal court in Sacramento, the Bee said.
The Fromme case was the first ever to include oral testimony from a sitting president in a criminal trial.
Fromme was released on parole in in 2009.
Ford survived a second assassination attempt, this one by Sara Jane Moore, who had been associated with radical groups. She was convicted sentenced to life in prison for the attempt and was paroled in 2007.
Ford died Dec. 26, 2006, at the age of 93.