Warren E. Hewitt, a legal and human rights specialist at the State Department, died Sept. 3 at a nursing home in Belmont, Mass. He was 91.

The cause was end-stage dementia, said his daughter, Jacqueline Hewitt.

Starting in 1951, Mr. Hewitt spent more than 25 years at the State Department and was chief of the human rights division from 1969 to 1974. He then oversaw legal and human rights affairs in the State Department’s office of U.N. political affairs.

His work often took him to Geneva, where he represented the United States at the U.N. Commission on Human Rights, the predecessor of the U.N. Human Rights Council.

Warren Edgar Hewitt was a native of Watertown, N.Y., and a 1943 graduate of Ursinus College in Collegeville, Pa. On the G.I. Bill, he attended Columbia University and received a master’s degree in international affairs and a law degree in 1950.

During World War II, he served in the Army’s 101st Airborne Division. He participated in Operation Market Garden, landing in a glider over the Netherlands on Sept. 17, 1944.

The operation was widely viewed as a calamitous Allied military assault behind German lines in the Netherlands. His involvement led to his career attempting to resolve conflict through international law, his daughter said.

He moved to Belmont from Falls Church last year.

His wife, Gertrude Graedel Hewitt, whom he married in 1948, died in 2005. Survivors include his daughter, Jacqueline N. Hewitt of Winchester, Mass.; and two grandsons.

— Samantha Raphelson