Walter A. Hamilton, 59, an officer of The Conference Board, a New York City research organization, who was a former Commerce Department official and Capitol Hill aide, died Thursday at his home in New York City after a heart attack.

He was a staff member of the old Congressional Joint Committee on Atomic Energy from 1947 to 1956, then was a vice president of the United Nuclear Corp., for 11 years. From 1967 to 1972, he was deputy assistant secretary of Commerce, first for domestic business policy and then for industry economics.

Since that time he had worked for The Conference Board, a private nonprofit business and economic research organization. At the time of his death he was the board's vice president for public affairs research.

Mr. Hamilton was a native of New York City and a 1943 graduate of Amherst College. He earned a master's degree in business administration at Harvard University in 1947. He served in the Army during World War II and was awarded the Legion of Merit.

Survivors include his wife, Ellen Hamilton of Severna Park; two sons, Craig of Mountain View, Calif., and Gordon of Scarsdale, N.Y.; a daughter, Laura Hamilton of Durham, N.H., and a sister, Cordelia Hamilton of Stony Point, N.Y.