Updated 5:52 p.m.
Nicholas Katzenbach, who served as attorney general during the Johnson administration, died Tuesday night at the age of 90.
Katzenbach's long legal career began in 1950 with a position as an attorney-advisor in the Office of General Counsel to the Secretary of the Air Force. He went on to serve as assistant attorney general from 1961-62 and as deputy attorney general from 1962-65. Following a little more than a year as the nation's 65th attorney general, he served as under secretary of state from 1966 to 1969.
Outside of the federal government, Katzenbach was an active law professor, teaching at Rutgers School of Law—Newark, Yale Law School and the University of Chicago Law School.
In one of his more widely publicized moments, Katzenbach, flanked by federal marshals, confronted Alabama Gov. George Wallace, who was attempting to physically block the entrance to the University of Alabama's Foster Auditorium in protest of the enrollment of two black students.
According to the New York Times, Wallace read a statement deriding the federal government for suppressing the rights of the university in selecting its students, to which Katzenbach replied, "I'm not interested in this show."
Katzenbach also fought FBI Director J. Edgar Hoover over the decision to tap Martin Luther King Jr.'s phone conversations, and supported President Bill Clinton during his impeachment hearing before the House Judiciary Committee.
By phone Wednesday, John Seigenthaler, a former press aide to Attorney General Robert Kennedy, said that while events like the University of Alabama standoff thrust Katzenbach into public light, "until the president's assassination, he was virtually invisible," working as a cool hand behind the scenes.
In one of his less-publicized moments, Seigenthaler said Katzenbach dictated over the phone the presidential oath of office to a member of then-Vice President Lyndon Johnson's staff, which was later used to swear in Johnson to become president on an airplane in Dallas.
At the Justice Department, Katzenbach was known for his broad understanding of all of the major cases the department was involved in, Seigenthaler said, a trait that set him apart from the narrowly focused associates on staff.
Justice Department associates "might have had background on one or two cases, but he had the background on all of them," Seigenthaler said. "You were talking to a man with a gifted legal mind, but he also had a biting sense of humor, and I don’t think there was ever a legal challenge he couldn't respond to," he added.
After leaving government service, Katzenbach joined IBM in 1969 as general counsel and helped steer the company through the Justice Department's 13-year antitrust case seeking the company's breakup, leaving for the New Jersey firm Riker Danzig Scherer Hyland & Perretti in 1986.
Glenn Clark, managing partner of Riker Danzig who worked alongside Katzenbach during his years at the firm, described him as "absolutely brilliant" and a "true giant" of the legal world who remained humble and level-headed despite his renown.
According to Clark, Katzenbach brought to the firm "a level of status and prestige that was second to none…There wasn't a lawyer in America that didn’t recognize his name."
In 1980, he testified on behalf of W. Mark Felt, who was eventually found guilty of ordering illegal wiretaps on civilians. Felt was later revealed to be the "Deep Throat" source cited by then-Washington Post reporters Carl Bernstein and Bob Woodward in their coverage of the Watergate scandal.
Katzenbach is survived by his wife, Lydia; sons Christopher and John; daughters Maria and Anne deBelleville Katzenbach; and six grandchildren.