Retired Navy Capt. Marvin M. Stephens, 79, who was secretary of the Joint Chiefs of Staff from 1947 until retiring from active duty in 1953, died Tuesday, at Bethesda Naval Hospital after a heart attack.

He served aboard submarines with both the Pacific and the old Asiatic fleets from the mid-1920s to mid-1930s. He later was an assistant machinery inspector at the Electric Boat Company works at New London, Conn.

Capt. Stephens was executive officer of the submarine base at Pearl Harbor from 1941 to 1943, then commanded a submarine division at New London. His later assignments concerned submarine construction.

After retiring from the Navy, he lived in Arlington and was a Washington representative for several moving and storage firms, including Republic Van Lines. He represented A. E. Prinkel Moving & Storage at the time of his death.

Capt. Stephens was a native of Alabama and a 1923 graduate of the U.S. Naval Academy at Annapolis. He was a 1925 graduate of the Navy's submarine school at New London. He also graduated from the Navy's postgraduate school and earned a master'hs degree in diesel engineering at Pennsylvania State University.

He was a member of the Washington Golf & Country Club and had been president of the Sertoma Club of Washington.

Capt. Stephens' wife, Roberta L., died in 1979.

Survivors include two sons, Marvin M. Jr., of Alexandria, and Franklin M., of New Canaan, Conn.; two sisters, Sarah Reed of Miami, and Ada Epps of Birmingham, Ala., and four grandchildren.