Born in New York on May 31, 1907, Morse graduated from Rutgers University in 1929, where he was a member of the Cap and Skull Society, and from the Harvard Law School in 1932. He was admitted to the New Jersey bar in 1932. He later became Special Assistant to the United States Attorney General, Chief Counsel of the Petroleum Labour Policy Board in the US Department of the Interior, and Regional Attorney for the National Labour Relations Board in the metropolitan area of New York.