J. Lawerence Hennessey, 63, a retired personnel program analyst with the Civil Service Commission, died Friday at Fairfax Hospital following a heart attack. He was stricken at his home in McLean.

Mr. Hennessey was born in Saratoga Springs, N.Y. He graduated from Union University in Schenectady.

He began his federal career as a representative of the Veterans Administration in New York state in the late 1930s. He served in the Army during World War Ii and then became a civilian personnel assistant at the Army's general depot in Schenectady.

In the early 1950s, he moved to Washington and was a program analyst in the office of the secretary of the Army in the Pentagon. He later transferred to the Civil Service Commission, from which he retired in 1969 for reasibs of health.

Mr. Hennessey's first wife, the former Jean Cuzzins, died in 1965.

Survivors include his wife, Anne Battaile Hennessey, of the home in McLean; a son, George, of Falls Church; a stepdaughter, Mary Dowrick, of Norfolk; a brother, John J., of Saratoga Springs, and two sisters, Elizabeth Coyne, of Long Island City, N.Y., and Mrs. Joseph La Bruyere, of Brooklyn N.Y. CAPTION: Picture, J. LAWRENCE HENNESSEY