James Selden Lay Jr., 75, a retired official of the Central Intelligence Agency who also was a former executive secretary of the National Security Council, died June 28 at the Veterans Administration Hospital in Perry Point, Md. He had Alzheimer's disease.

Mr. Lay was named assistant executive secretary of the NSC when it was established in September 1947. Before that, he had served with Army intelligence during World War II and worked for the State Department.

In January 1950, he succeeded Navy Rear Adm. Sidney W. Souers as the council's executive secretary and he held that job until 1961 when he transferred to the CIA. He was deputy assistant to Allen W. Dulles, head of the CIA, and then executive secretary of the U.S. Intelligence Board. He retired in 1971 but remained a consultant to the President's Intelligence Advisory Board until 1977.

Mr. Lay, a resident of Falls Church, was born in Washington. He graduated from McKinley Technical High School and the Virginia Military Institute, where he studied electrical engineering. He received a master's degree in business administration from Harvard University.

Before World War II, he worked for Vepco in Richmond, the Stone and Webster Service Corp. in New York, and the Hagerstown Gas Co. A reserve Army officer, he was called to active duty in May 1941.

By the end of the war, he was secretary of the joint intelligence committee of the Joint Chiefs of Staff and U.S. secretary of the Combined Intelligence Committee. He retired from the Reserves as a colonel in 1971.

After the war, he was secretary of the old Central Intelligence Group's national intelligence authority, then worked in the office of the special assistant to the secretary of state for research and intelligence. He left State to join the NSC.

Mr. Lay's military decorations included the Legion of Merit. He also held the CIA's Distinguished Intelligence Medal and was a 1964 recipient of the National Civil Service League's Career Service Medal.

He served on the Falls Church School Board from 1949 to 1951 and from 1961 to 1964. He was a member of St. James Catholic Church and the Sons of the American Revolution.

Survivors include his wife of 50 years, the former Emily Graham Miller, of Falls Church; three daughters, Carolyn Dowd of Gaithersburg, Emily O'Connell of Seattle, and Patricia Dorsey of Grosse Pointe Farms, Mich., and four grandchildren.