Robert Sargent Shriver Jr., known as Sarge from childhood, was born in Westminster, Md., on Nov. 9, 1915, the son of his namesake, a banker, and Hilda Shriver. He attended Canterbury, a Catholic boarding prep school in New Milford, Conn. — John F. Kennedy was briefly a schoolmate — and Yale University, graduating with honors in 1938. He earned a Yale law degree in 1941. After the war, he joined Newsweek as an editor. He met Eunice Kennedy at a dinner party, and she introduced him to her father, Joseph P. Kennedy. In 1946, Joseph Kennedy hired him to help manage his recently acquired Merchandise Mart in Chicago, then the world’s largest commercial building. In Chicago, Mr. Shriver not only turned a profit for the mart but also plunged into lay Catholic affairs and Democratic politics. Mr. Shriver and Ms. Kennedy were married by Cardinal Francis Spellman at St. Patrick’s Cathedral in New York in 1953. Eunice Shriver died in 2009. He brought President Kennedy’s proposal for the Peace Corps to fruition in 1961 and served as the organization’s director until 1966. In 1968, President Johnson named Mr. Shriver ambassador to France. Senator McGovern, the Democratic presidential nominee, picked him as his running mate. Mr. McGovern’s first choice, Senator Thomas F. Eagleton, was dropped after revelations that he had received electroshock therapy for clinical depression. In later years, he was a rainmaker for an international law firm, Fried, Frank, Harris, Shriver & Jacobson, and he retired in 1986. In addition to Maria Owings Shriver, he is survived by four sons, Robert Sargent Shriver III of Santa Monica, Calif., Timothy Perry Shriver of Chevy Chase, Md., Mark Kennedy Shriver of Bethesda, Md., and Anthony Paul Kennedy Shriver of Miami; and 19 grandchildren.