Marchetti was born in Hazleton, Pennsylvania. From 1951 to 1953, he served as a corporal in U.S. Army Intelligence in France and Germany. Returning to the U.S. after his military service, he enrolled in Pennsylvania State University, where he majored in Russian area studies, graduating with a bachelor's degree in history in 1955.
After leaving the CIA, Marchetti began a writing career. His first work was a novel, The Rope-Dancer, published in 1971. The plot involves an officer in the "National Intelligence Agency" who becomes a spy for the Soviet Union. During public appearances promoting his novel, Marchetti announced that he was writing a non-fiction work on the CIA. In March 1972, he completed a draft of an article for Esquire which, according to a later CIA account, included "names of agents, relations with named governments, and identifying details of ongoing operations." The CIA received a copy of the article and decided to seek an injunction against its publication. The basis for seeking an injunction against Marchetti was the secrecy agreement which he had signed when beginning employment at CIA. CIA presented the agreement, and the parts of the draft article it considered in violation of the agreement, to Judge Albert V. Bryan, Jr. of the US District Court for Eastern Virginia, who granted a temporary restraining order in April 1972. The case proceeded to trial, at which Bryan found for the CIA and issued a permanent injunction requiring Marchetti to submit his writings to CIA for review prior to publication. Marchetti appealed the injunction to the Fourth Circuit Court of Appeals, which upheld Bryan's restraint but limited it to classified material. The appeals court also found that Marchetti was entitled to timely review of materials he submitted to the CIA. Marchetti appealed again to the US Supreme Court, but the Court rejected Marchetti's appeal in December 1972. Marchetti continued work on his book with a co-author, John D. Marks, and signed a book contract with publisher Alfred A. Knopf. In August 1973, they submitted their manuscript to the CIA. After reviewing the manuscript, the Agency responded with a list of 339 passages which it claimed were classified information and demanded their deletion. Marchetti and Marks rejected the demand and indicated they would go to court to print the manuscript as written. The CIA then withdrew its objections to 171 of the items but stood firm on the remaining 168. The trial was held again before Judge Bryan. This time, however, he rejected all but 26 of the deletions requested by the CIA on the grounds that the information in them was not properly or provably classified. The CIA appealed Bryan's ruling, and ultimately the Fourth Circuit Court of Appeals upheld all 168 of the deletions. The book was published by Knopf in 1974 as The CIA and the Cult of Intelligence. It was printed with blanks for deleted passages and boldface type for the 171 deletions which CIA originally requested and later withdrew.
Later writing
In 1978 Marchetti published an article about the JFK assassination in the far-right newspaper of the antisemiticLiberty Lobby, The Spotlight. Marchetti, a proponent of the organized crime and the CIA conspiracy theory, claimed that the House Select Committee on Assassinations revealed a CIA memo from 1966 that named E. Howard Hunt, Frank Sturgis and Gerry Patrick Hemming in the JFK assassination. Marchetti also claimed that Marita Lorenz offered sworn testimony to confirm this. The HSCA reported that it had not received such a memo and rejected theories that Hunt was involved in a plot to kill Kennedy. In 1981, E. Howard Hunt sued the Liberty Lobby and Marchetti for defamation and won $650,000 in damages. Liberty Lobby, represented by attorney Mark Lane, appealed the verdict. On February 1, 1985, Marchetti stated that key parts of his articles were based upon rumors that he heard from Penthouse columnist Bill Corson and that he had no corroboration of Corson's story. Corson had provided an earlier deposition stating that he not discussed the rumors with Marchetti. Marchetti, Liberty Lobby and Lane won the appeal in 1985. Commenting afterward, two jurors rejected that the conspiracy theories offered by Lane influenced the verdict. Lane's 1991 book Plausible Denial, develops the claims he presented in the trial.