After graduating from Yale, Holt worked for nine years in the railroad business, holding positions first with the Southern Railway and subsequently with the Delaware, Lackawanna and Western Railroad. From 1912 to 1946, he was associated with the Central Hanover Bank & Trust in New York City. In 1920, he was promoted to vice president in 1920. He also served for a time as the president of the Central Hanover Safe Deposit Company. In later years, he was the vice president in charge of Hanover Bank's Madison Avenue and 42nd Street branches before retiring in 1946. Holt was also active in the International Grenfell Association, the New York Women's League for Animals, the 42nd Street Property Owners and Merchants Association, and the Near East College Association.
Holt was married to Margaret Sumner Carson in 1919. They had three children, Margaret Carson Holt (born September 1920), Mary Bowen Holt (born April 1924), and Susanna Aspinwall Holt (born April 1924). Holt lived at Chandler Farms in Pomfret, Connecticut. He died in 1955 at age 74 in Putnam, Connecticut.