Lawrence Walsh, an attorney best known as the chief prosecutor in the criminal investigation of the 1980s arms-for-hostages deal known as Iran-Contra, has died at age 102.

Walsh, who achieved prominence in private practice, public service and the organized bar in a legal career spanning more than a half-century, died on March 19 at his home in Oklahoma City, the hometown of his second wife, Mary Alma Porter.

He retired to Oklahoma in 1982, after working for more than 20 years at Davis Polk & Wardwell in Manhattan.

But Walsh came out of retirement at age 74 for what turned out to be the role for which he is best-remembered: the court-appointed independent counsel in the complex and clandestine Iran-Contra case.

Other highlights of his career were as assistant district attorney to Manhattan prosecutor Thomas Dewey from 1936-41; assistant counsel and chief counsel to governor Dewey from 1943-51; judge for the U.S. District Court for the Southern District of New York from 1954-57; a deputy U.S. attorney general from 1957-60 and as a negotiator in 1969 in the U.S. delegation at the Paris Peace Talks with North Vietnam.

Walsh also served as president of the New York State Bar Association in 1966-67 and of the American Bar Association in 1975-76.

“Lawrence Walsh left a deep and lasting impact on the legal community and the citizens of the United States through his vigorous advocacy for the rule of law and fairness in the judicial process,” said David Schraver, the current president of the state bar.

Schraver said Friday that Walsh’s tenure as state bar president is remembered for his advocacy for the oppressed, to eliminate partisanship as a factor in the re-election of sitting judges and for backing an initiative to build new courthouses.

The son of a doctor, Walsh was born on Jan. 8, 1912, in Port Maitland, Nova Scotia. He moved with his family to Queens when he was 2 and became a naturalized U.S. citizen when he was 10.

Walsh attended Columbia University and Columbia University Law School, graduating with a law degree in 1935.

While working summers during college as a merchant seaman, Walsh said he learned valuable lessons for his legal career through the “rough treatment” he got from fellow seamen.

“I enjoyed very much going to sea,” he said in an interview to mark his 100th birthday for the State Bar News’ April/May issue in 2012. “It was very helpful because I got to deal with people that I hadn’t known before.”

A stint at Davis Polk from 1941-43 presaged a longer affiliation with the firm from 1961 to 1981.

A protege of Walsh’s at Davis Polk, Guy Struve, said his long association with Walsh began the first day Struve walked into the firm in 1967.

“He was extraordinary,” Struve said in an interview Friday from Oklahoma City. “He was very hard on himself and the people who worked for him in the sense that nothing less than the best was acceptable.”

Struve added, “For some people, that made it less than a fun experience to work for him. For me, it was terrific because you never met such an able lawyer and such a principled lawyer and I never stopped learning from it.”

Walsh headed the Iran-Contra investigation, in which the life-long Republican was tapped to unravel an arrangement in which the Reagan administration sought to sell arms to Iran in an effort to gain the release of western hostages being held in the Middle East. Proceeds from the sales were then to be used to give aid—which had been expressly blocked by Congress—to the rebels called Sandinistas who were trying to topple a Marxist regime in Nicaragua.

Convictions won by Walsh and his investigators against the key figures in the affair, Lt. Col. Oliver North and Adm. John Poindexter, were overturned by a court. Former defense secretary Caspar Weinberger was under indictment for concealing knowledge of the scandal when he was pardoned by President George H.W. Bush. Bush also pardoned five other defendants in the case.

In a 1997 book about the investigation, “Firewall, The Iran-Contra Conspiracy and Cover-Up,” Walsh said he believed that the rule of law had been thwarted through a cover-up of a conspiracy engineered in the White House during Reagan’s term and completed by Bush.

Struve said Walsh did not regret his work on Iran-Contra or the criticism he received from both Democrats and Republicans during the investigation.

“He approached that job as one where his duty was to follow the facts and the law where they led and he did that,” Struve said. “The nature of a job like that is that the subject matter is sometimes highly political. That’s why they have an independent counsel doing it rather than the Department of Justice. He understood that criticism came with the job.”

Walsh was of counsel to the law firm of Crowe and Dunlevy after moving to Oklahoma in 1982.

Speaking to the State Bar News in 2012, Walsh said he missed the rhythms of working each day at a law firm: “I miss the associations that went with it,” he said. “You were never alone at a firm. A firm keeps you alert. You felt stimulated by the work and there is a deep sense of support.”

Walsh also wrote a 2003 autobiography, “The Gift of Insecurity: A Lawyer’s Life.”

Walsh’s first wife, Maxime Winton, died in 1964. His second wife, Mary Alma Porter, died in 2012.

He is survived by his children, Barbara Marie Walsh, Janet Maxine Walsh, Sara Porter Walsh, Dale Edward Walsh, and Elizabeth Porter Walsh, four grandchildren and two great-grandchildren.

A memorial service was planned for March 22 in Oklahoma City. A memorial service in New York will be announced at a later date, Struve said.