Moody was born in New Haven, Connecticut and attended the public schools in Providence, Rhode Island. He graduated from Brown University with a degree in economics in 1922. He was an instructor in history at the Moses Brown Preparatory School in Providence 1922-1923.

Moody moved to Detroit, Michigan and was a reporter covering Washington, D.C., for the Detroit News 1923-1951 which was owned by his uncle, William Scripps. He was a correspondent for Barron’s Financial Weekly 1934-1948 and also wrote extensively for the North American Newspaper Alliance and the Bell Syndicate. Moody was a combat war correspondent in 1944, covering World War II in Italy, Africa, the British Isles, the Middle East, and Iran. He moderated a radio and television program Meet Your Congress 1946-1952. He was a foreign correspondent 1947-1948.

Moody was appointed on April 22, 1951, as a Democrat to the United States Senate to fill the vacancy caused by the death of Arthur H. Vandenberg and served from April 23, 1951, to November 4, 1952. He was an unsuccessful candidate for election to fill the vacancy and also for election to the full term, being defeated by Republican Charles E. Potter. He resumed his newspaper and radio career. He died in Ann Arbor, Michigan, while campaigning for the Democratic nomination for United States Senator, of a heart attack following complications of viral pneumonia. Blair Moody is interred at Woodlawn Cemetery in Detroit.