Iran-contra special prosecutor Lawrence E. Walsh speaks to reporters in Washington in 1989. (Rick Bowmer/AP)

Lawrence E. Walsh, a New York corporate lawyer with impeccable Republican credentials who as independent counsel prosecuted several key players in the Reagan-era Iran-contra scandal only to see the convictions overturned on appeal and many other officials pardoned, died March 19 at his home in Nichols Hills, Okla. He was 102.

His death was confirmed by Kevin Gordon, president of the Crowe & Dunlevy law firm, with which Mr. Walsh had been associated. The cause was not immediately available.

Mr. Walsh began his career as a Depression-era racket buster under New York District Attorney Thomas E. Dewey in the late 1930s and later served as a federal district judge in New York and deputy attorney general of the United States. He also was a president of the American Bar Association.

He spent most of his career as a partner at Davis Polk & Wardwell, one of the most powerful law firms in the country, where he did civil litigation for such corporate clients as AT&T, R.J. Reynolds and General Motors. In 1969, he served briefly as deputy to chief negotiator Henry Cabot Lodge during peace talks with North Vietnamese communists.

In retirement, Mr. Walsh gained his greatest public profile. On Dec. 19, 1986, then-Attorney General Edwin Meese III appointed him special prosecutor to launch an inquiry into what at the time was considered the worst government scandal since Watergate. Mr. Walsh spent nearly seven years and $39 million as the special prosecutor in the Iran-contra scandal.

The investigation would conclude that the administration of President Ronald Reagan had illegally sold arms to Iran to win the release of U.S. hostages in the Middle East and had given the proceeds, in defiance of Congress, to a rebel group known as the “contras,” who were fighting to overthrow the Marxist government of Nicaragua.

Congress also created a joint investigative committee, which many thought would lead to Reagan’s impeachment.

The Iran-contra affair led to the dismissal of the president’s national security adviser, Navy Adm. John M. Poindexter, and Marine Lt. Col. Oliver North, the National Security Council staff aide accused of masterminding the scheme.

Poindexter and North were among 14 officials who faced criminal charges. They also were among the 11 convicted, although their convictions were set aside by appellate court decisions. Five — including former State Department official Elliott Abrams and former defense secretary Caspar W. Weinberger — were pardoned by President George H.W. Bush on Christmas Eve 1992.

Mr. Walsh concluded that there was “no credible evidence” that Reagan broke the law but that the president set the stage for the illegal activities of others.

Even though no one went to jail in the long-running inquiry, Mr. Walsh told The Washington Post in 1991 that the probe of what he called a “national security crime” was important in the long term. “Jail sanctions are important, and they would have been justified in several of the cases we brought, but the deterrent effect is there from the conviction itself,” he said.

Lawrence Edward Walsh was born Jan. 8, 1912, in the fishing hamlet of Port Maitland, Nova Scotia. His maternal grandfather was a sea captain. Although the family left Canada when Mr. Walsh was 2, he returned every summer until he was 12 to stay with his grandparents.

His father, a doctor, moved the family to the New York City borough of Queens.

His father died when Mr. Walsh was 15, leaving him, his mother and his sister in financial peril. He worked his way through college and law school at Columbia University by clerking in a bookstore, doing Christmas duty at the post office and working two hours a day in the cafeteria. Each summer, he went to sea, mostly on steamships, and worked as everything from a bellboy to a seaman.

He graduated from Columbia College in 1932 and Columbia Law School in 1935, in the midst of the Depression. It was hard to find a job, he told The Post in 1993, and when he did — as a special assistant attorney general on a Brooklyn bribery investigation — he worried about losing it. He resolved to be the hardest-working young lawyer in the city.

“I remember figuring out to myself that if I had one night at home a week, it was better than average,” he said. He was 24 and making $1,800 a year.

Around this time, he married Maxine Winton, who died in 1964. He married Mary Porter in 1965. Complete information about survivors was not immediately available.

In 1937, Dewey — a future two-time Republican presidential candidate — was elected Manhattan district attorney. He began putting together a staff of young prosecutors who were honest, incorruptible and willing to work 16-hour days. From thousands of applicants, Mr. Walsh was one of the 70 who were chosen. Judges called them the “boy scouts.”

In 1941, Mr. Walsh left the district attorney’s office for Davis Polk & Wardwell. He told the New York Times that he was looking for security. “I’d been out of law school five years and never knew where I was going to be very long,” he said. “Davis Polk never fired anybody.”

His stay was brief. Dewey was elected governor of New York in 1942, and he sought out Mr. Walsh to be an assistant counsel. Mr. Walsh later became the governor’s chief counsel. He also worked in Dewey’s second unsuccessful presidential campaign, in 1948, and for the rest of his life, he referred to himself as “a Dewey Republican.”

In 1954, President Dwight D. Eisenhower named Mr. Walsh to the federal bench in Manhattan, but when William P. Rogers, a former colleague in the New York district attorney’s office, became U.S. attorney general, he asked Mr. Walsh to join him as chief deputy. Mr. Walsh oversaw the selection of federal judges and the integration of the public schools in Litttle Rock.

With the election of Democrat John F. Kennedy to the presidency in 1960, Mr. Walsh returned to Davis Polk. He was a Wall Street super lawyer who, as the New York Times noted in 1987, resembled a character out of a Louis Auchincloss novel about Wall Street lawyers: “He has grayed at the temples; there is never a hair out of place. His wardrobe is a sea of dark suits and white shirts, usually worn with a plain tie and well-polished black shoes.”

In 1969, he led the American Bar Association committee that found President Richard M. Nixon’s nominees Clement F. Haynsworth Jr. and G. Harrold Carswell qualified for the U.S. Supreme Court. The Senate rejected both nominees, and the bar association and Mr. Walsh received strong criticism.

In 1981, Mr. Walsh retired from Davis Polk and moved to Oklahoma City, his wife’s home town, where he joined Crowe & Dunlevy. He was in semi-retirement when he was appointed Iran-contra special counsel.

During the Iran-contra investigation, Mr. Walsh established a three-city operation — Washington, New York and Oklahoma City — that included teams of lawyers and support staff from the Customs Service, the FBI and the Internal Revenue Service.

In 1993, a lawyer who had worked on the investigation told The Post that he recalled delivering papers to Mr. Walsh’s hotel late at night. “And he was still working — in a coat and tie, at the little hotel desk,” the lawyer said, “as though this was what everybody does at 11 o’clock at night when they’re 75 years old.”

On March 16, 1988, a grand jury handed down a 23-count indictment against North, Poindexter and other top administration officials. Each defendant was tried separately.

After the trials of the major figures, Mr. Walsh focused on individuals suspected of having assisted or having falsely denied knowledge of Iran-contra activities, leading to criminal charges against 10 people. Seven were convicted. One CIA official’s case was dismissed on national security grounds, and Bush, who had been Reagan’s vice president at the time of the scandal, pardoned two defendants before their trials.

“By then,” John B. Judis wrote in the New York Times in 1997, “Walsh had become a Lear figure, roaming the moors of Washington, railing privately against Bush, the Senate minority leader, Bob Dole, and his other detractors.”

Mr. Walsh continued to insist that the investigation uncovered information the American people needed to know.

“The underlying facts of Iran/contra,” he concluded in his official report, released on Aug. 4, 1993, “are that, regardless of criminality, President Reagan, the secretary of state, the secretary of defense and the director of central intelligence and their necessary assistants committed themselves, however reluctantly, to two programs contrary to congressional policy and contrary to national policy. They skirted the law, some of them broke the law, and almost all of them tried to cover up the President’s willful activities.”

In his book “Firewall: The Iran-Contra Conspiracy and Cover-Up” (1997), Mr. Walsh maintained that the architect of the coverup was Meese, abetted by Bush, White House Chief of Staff Donald T. Regan, CIA Director William J. Casey, Weinberger and other top administration officials.

“What set Iran-contra apart from previous political scandals,” Mr. Walsh wrote, “was the fact that a cover-up engineered in the White House of one president and completed by his successor prevented the rule of law from being applied to the perpetrators of criminal activity of constitutional dimension.”