Morse was born in Lowell, Massachusetts on August 7, 1921 and graduated from Boston University in 1948 and from Boston University School of Law in 1949. He served in World War Two in the Army from 1942-1946. After the war, he served as a private practice lawyer, business executive, law clerk to Chief Justice of the Supreme Judicial Court of Massachusetts, and professor at Boston University School of Law, 1949-1953. He was elected to the Lowell City Council in 1952 and served there until 1953 when was employed as a staff member for United States Senate Armed Services Committee, a position he would hold until 1955. In 1955 until 1958 he served as an executive secretary and chief assistant to United States Senator Leverett Saltonstall, and later as a deputy administrator of Veterans Administration from 1958-1960. After the death of Edith Nourse Rodgers in September 1960, he was selected by the Republican Party to take her place on the ballot and was elected as a Republican to the Eighty-seventh Congress in November of 1960. He was then reelected to the five succeeding Congresses (January 3, 1961- May 1, 1972) before becoming Under Secretary General for Political and General Assembly Affairs at the United Nations from 1972-1976 and later Director at the United Nations Development Program from 1976-1986. He died at his home in Naples, Florida on December 18, 1994, and was cremated and placed in Arlington National Cemetery, Arlington, Va.