Lucien Nedzi was born in Hamtramck, Wayne County, Michigan, on 28th May, 1925. His education at the University of Michigan was interrupted by the Second World War. Nedzi joined the United States Army and served as a combat infantryman in the Philippines and Japan.

Nedzi graduated from the Michigan Law School in 1951. He remained a member of the United States Army Reserve (1946-53) and served briefly in the Korean War.

A member of the Democratic Party Nedzi worked as a lawyer in Wayne County and as a public administrator (1955-61). Nedzi was elected to the 87th Congress to fill the vacancy caused by the resignation of Thaddeus M. Machrowicz. He was reelected to the nine succeeding Congresses.

Nedzi was chairman of the Select Committee on Intelligence during the Watergate Scandal This included the investigation of the role played by CIA officials and assets such as E. Howard Hunt, James W. McCord and Lee R. Pennington in the break-in and subsequent cover-up.

An unnamed CIA official told the Select Committee on Intelligence that: "He (Edward F. Saye) told me at the time... that Mr. Lee Pennington had entered Mr. McCord's office at home, destroying any indication of connections between the Agency and Mr. McCord." The head of the Security Research Staff said that "Pennington was too sensitive and the decision had been made to sacrifice Cecil Pennington instead".

In August, 1972, Richard Helms told Stephen L. Kuhn, the deputy director of the Office of Security, to "Remove the (Pennington) materials from the (Watergate) files and maintain them separately." This message was passed to another CIA officer who refused to comply with the order. He remarked to another officer that the "Agency did not need its own L. Patrick Gray". This was a reference to L. Patrick Gray, the director of the FBI who destroyed the documents in the White House safe of E. Howard Hunt. The two officers placed the Pennington materials in a sealed envelope and marked it for the director's "Eyes Only". In August, 1973, the new CIA director, William Colby, asked to see all files related to the Watergate Scandal. Kuhn instructed the CIA official given this responsibility to collect these documents together, that he was not to include the Pennington envelope in the materials given to Colby.

When interviewed by the Nedzi, Richard Helms admitted that during the Watergate investigation he ordered the erasure of all tapes and transcripts of conversations secretly recorded in his office and the French Room (a conference room used by senior officials of the CIA). More than four thousand pages of recorded conversations over a six year period were destroyed.

Helms had been instructed by Mike Mansfield that all documents relating to Watergate had to be preserved. Helms told Nedzi that the destroyed materials had nothing to do with Watergate: "When I heard about tapes and destruction of Watergate-related tapes, the thing that immediately struck me was: "who knows what was on those tapes except me or my secretary? Who in the public can make an allegation that there were any tapes that were Watergate-related?" Nedzi replied: "The problem is... how can you prove they weren't Watergate-related."

In his book Secret Agenda, Jim Hougan alleges that Lee R. Pennington was providing Lou Russell and James W. McCord with CIA reports on people like Jack Anderson that were being targeted by those involved in Operation Sandwedge. Hougan claims that "Lee R. Pennington was McCord's cut-out to the Security Research Staff."

William Colby was eventually given the Pennington file. On 28th June, 1974, he reported to Howard Baker: "The results of our investigation clearly show that the CIA had in its possession, as early as June, 1972, information that one of its paid operatives, Lee R. Pennington, Jr., had entered the James McCord residence shortly after the Watergate break-in and destroyed documents which might show a link between McCord and the CIA."

Lucien Nedzi resigned from Congress in 1980 and retired to McLean, Virginia.