Bennett Boskey, whose legal career in Washington spanned 75 years, served in the Army during World War II. He died May 11 at his home in Bethesda, Md., at age 99. (US Army)

Bennett Boskey, whose legal career in Washington spanned 75 years, including a U.S. Supreme Court clerkship in 1940 and ending with the closing of his law office in 2015, died May 11 at his home in Bethesda, Md. He was 99.

The cause was congestive heart failure, said a nephew, Andrew Ludwig.

Over the course of his career, Mr. Boskey’s work included litigation, corporate transactions, probate matters, regulatory issues, government contracts, nuclear energy and public utilities. The people he had as clients ranged from the wealthy and powerful to the indigent.

From 1951 to 1996, he was a partner in the firm that became Volpe, Boskey and Lyons. When the firm dissolved in 1996, he opened a solo practice, which he maintained for an additional 19 years.

Bennett Boskey was born in New York City on Aug. 14, 1916. He graduated in 1935 from Williams College in Massachusetts, studied economics at the University of Chicago for a year and then graduated in 1939 from Harvard Law School.

He was a law clerk for a year for Judge Learned Hand of the U.S. Court of Appeals for the 2nd Circuit in New York and then came to Washington, where he clerked at the Supreme Court for Justice Stanley Reed and then Chief Justice Harlan Fiske Stone.

After Army service in World War II, he worked at the State Department as an adviser on peace treaties with Italy and other countries and on issues involving property owned by wartime enemies of the Allied powers.

Before entering private practice, he was an attorney for the Atomic Energy Commission.

Mr. Boskey argued several cases before the Supreme Court and wrote extensively on matters related to practice before the high tribunal.

From 1975 to 2010, Mr. Boskey was treasurer of the American Law Institute, a scholarly organization focused on laws and legal matters.

His wife, Shirley Ecker, whom he married in 1940, died in 1998. There are no immediate survivors.