Lady Bird Johnson said the film "falsely and irresponsibly" accuses her husband of conspiring to kill President Kennedy.
No accusation made against Johnson "has hurt as painfully," the 91-year-old former first lady said in a Jan. 29 letter. Her husband died in 1973.
Copies of her letter were sent to the chief executives of three companies that own A&E Networks, which includes the History Channel. The letters went to Bob Wright of NBC, Victor Ganzi of Hearst Corp. and Michael Eisner of The Walt Disney Co.
Former Presidents Ford and Carter also sent letters citing the documentary, "The Guilty Men," which aired last November as part of a series of History Channel specials on the Nov. 22, 1963 assassination.
Ford, noting that he is the only surviving member of the Warren Commission that determined Lee Harvey Oswald acted alone in killing Kennedy, called the History Channel documentary "reprehensible."
Alleging that Johnson, as Kennedy's vice president, was part of a conspiracy to murder him is "the greatest, most damaging accusation ever made against a former vice president and president in American History," Ford, 90, wrote in his Jan. 23 letter.
The letters were released Monday to The Associated Press by Tom Johnson, chairman of the LBJ Foundation and a representative of the Johnson family.
Calls to NBC and Disney were not immediately returned.
"We don't comment on correspondence with our chief executive officer," said Hearst spokesman Paul Luthringer.
Tom Johnson said he and three other former Johnson aides planned to meet Wednesday with executives of the History Channel and A&E Television Networks to press for an investigation and for its findings to be made public.
Nickolas Davatzes, president of A&E Television Networks, is expected to take part, History Channel spokeswoman Lynn Gardner said Tuesday.
Other former Johnson aides scheduled to participate are Jack Valenti, now head of the Motion Picture Association of America; journalist Bill Moyers; and attorney Larry Temple.
"I'm puzzled, bewildered, that a distinguished enterprise like the History Channel would put on the air such garbage, such ugliness," Valenti said in November. "It makes one sick."
When the Kennedy series aired, the History Channel said in a statement that the point of view in "The Guilty Men" was "meticulously researched."
"By presenting different viewpoints we enable our viewers to decide to agree or disagree with them and to arrive at their own conclusions," the channel said.