Jerome K. Walsh Jr., a lawyer who served as a special civilian counsel on an Army panel investigating the 1968 My Lai massacre in Viet Nam and a former partner at Windels Marx Lane & Mittendorf, LLP, died peacefully on Monday, August 8 after a short illness. He was 84.

Born in Kansas City, Mo., to Jerome K. Walsh Sr. and the former Mary Lawler, he was a third generation attorney.

Jerry was the consummate lawyer and it suited his character, focusing his practice on litigation and corporate representation for many prominent clients who relied on him for his intellect and superior judgment. A graduate of Georgetown and the University of Michigan Law School, he served as associate editor of the Michigan Law Review. After several years at Sullivan & Cromwell, he founded Walsh & Frisch in 1965 and, after a merger in 2000, served as a partner, then counsel, of Windels, Marx, Lane & Mittendorf, LLP. In spite of his age, Jerry never retired, and until undergoing surgery in May, still went to the office every day where he worked on various estate matters.

He served with Robert McCrate as special counsel for the Department of the Army Review of Preliminary Investigations into the My Lai Incident (1969-1970). Headed by Lieut. Gen. William R. Peers, the panel was assigned to investigate the massacre by American troops of several hundred civilians in the hamlet of My Lai in March 1968. Its goal was to determine what had happened and whether Army officers had tried to cover up the episode.

An early report delivered by the commanding officer on the scene at My Lai stated only that 20 civilians had been killed accidentally during a military operation. Information supplied later by American witnesses led the Army to charge Lieut. William L. Calley, in secret, with the murder of 109 civilians. When the news about Lieutenant Calley and details about the massacre became public, pressure mounted for a full investigation. By bringing in civilians the Army hoped to reassure critics of the war that the new investigation would not be a whitewash.

Mr. Walsh was inspired to enter the legal profession by his grandfather, Frank P. Walsh. A noted labor lawyer, he was appointed chairman of the National Industrial Relations Commission by President Woodrow Wilson in 1913 and to the New York State Power Authority by President Franklin D. Roosevelt in 1931. He also served as co-chairman of the War Labor Board during World War I, becoming one of the chief architects of the legislative struggle against industrial exploitation of children and an advocate of Irish and anti-imperialist causes.

Lured to the Vineyard in the 1950s by fellow Kansas Citians Tom and Rita Benton, in 1961 Jerry and his former wife Cynthia Walsh settled into the Cleaveland House on Old County Road where he passed many a wonderful summer with his family and Island friends. Arriving every Friday evening from New York city, he would jump out of the car in his Brooks Brothers suit and head immediately to his backyard garden to check the progress of his prized tomatoes and radishes. There he would stand in the setting sun, cocktail in hand, watering his garden in his city shoes.

A longtime resident of New York’s Upper East Side, Jerry was a true gentleman who generated a quiet and calming respect and whose advice was always taken seriously. Simultaneously thoughtful and gregarious, his wonderful, wry sense of humor and fun belied his buttoned-down appearance and demeanor. Loved by family and friends, he will be dearly missed.

Mr. Walsh is survived by his beloved partner, Janet Rich; his daughters, Lawler Walsh Parker and Katherine Walsh; his sons in law, Terry Parker and Bruce Fernie; his daughter in law, Colette Dumont; his grandchildren, Maddie and Aidan Parker, Bowen and Avery Fernie, and Ella Claire, Henri and Audrey Walsh; and his sisters, Mary Lawler Abbott, Michaela Walsh, Sarah McClanahan and Deirdre Supino. His son James Walsh died in 2011.

In lieu of flowers, please consider making a donation to Benilde Hall in Kansas City, Mo.