Allan Gerson, a self-described dreamer whose family fled Nazi-occupied Poland under a false name and who became a prominent international lawyer representing victims of human rights abuses and terrorist attacks, died Dec. 1 at his home in Washington. He was 74.

The cause was complications of Creutzfeldt-Jakob disease, a degenerative brain disorder, said his wife, cookbook author Joan Nathan.

A man of many passions, he was also fine art photographer whose works are displayed in various museums and inspired a line of jewelry he designed by transferring photographic images onto gold and silver.

Mr. Gerson found solace in the quiet beauty of Chilmark, where he and Ms. Nathan built a home nearly two decades ago and where he enjoyed summer vacations with friends and family.

“He especially loved having breakfast alone at the Beach Plum Inn alone overlooking the water, and enjoying the finer things in life at Lennox and Harvey and stores with purpose and intention and design,” said his daughter Merissa.

Mr. Gerson was perhaps best known for originating the legal theory by which victims of terrorist attacks could sue foreign governments. His efforts resulted in a successful lawsuit against Libyan government for its role for supporting terrorists who bombed Pan Am Flight 103, which exploded over Lockerbie Scotland in 1988 killing 270 people.

Born in Samerkand, Uzbekistan in 1945, the son of Polish Jews who had been deported and imprisoned in Siberian labor camps, he and his family came to the United States in 1950 from Poland using another family’s visa.

In a commentary in The Washington Post in 2017, he referred to himself as a “dreamer,” comparing himself to the 700,000 undocumented immigrants who arrived as children and are now threatened with possible deportation.

“But for dint of circumstance, I might be in their boots,” he wrote.

Mr. Gerson studied economics at the University at Buffalo in New York, graduating in 1966. He received a law degree from New York University in 1969, a master of laws degree from the Hebrew University of Jerusalem in 1972 and a doctor of juridical science from Yale University in 1976.

While in Jerusalem, he met Joan Nathan at the Western Wall. They were married in 1974.

As a young lawyer, he worked for the Justice Department, pursuing Nazi war criminals who had fled to the United States, and later served as senior counsel to two U.S. ambassadors to the United Nations, Jeane J. Kirkpatrick and Vernon A. Walters, before entering private practice.

In addition to his wife and daughter Merissa, he leaves two other children, Daniela Gerson and David Henry Gerson, both of Los Angeles; a brother, Sam; and two grandchildren.

A graveside service was held Dec. 5 at the Martha’s Vineyard Hebrew Cemetery in Vineyard Haven.