Thomas G. Carney, 77, who retired in 1979 as head of the Washington office of Simpson, Thacher & Bartlett, a law firm based in New York City, died Nov. 3 at Holy Cross Hospital following a heart attack.

Mr. Carney, who lived at Rossmoor Leisure World in Silver Spring, was born in Blue Lick, Ind. He attended Notre Dame University and moved to Washington in the late 1920s to attend Georgetown University, where he earned a law degree in 1929.

In the 1930s, he worked on the staff of a congressional tax writing committee and as an attorney in the Justice Department. In 1940, he joined Simpson, Thacher & Bartlett in New York.

During World War II, he served in the Army in the Philippines. He then opened Simpson, Thacher & Bartlett's Washington office.

Mr. Carney was a past president of the Metropolitan Police Boys Club and the Manor Country Club. He also was a member of the Burning Tree Club, the Army & Navy Club and the Military Order of the Carabao, an organization of veterans of the Philippines. He was a member of St. Patrick's Catholic Church in Norbeck, Md.

Survivors include his wife, Marion, a brother, Allan A., and a sister, Virginia Castleberry, all of Rossmoor.