Graduated from St. Mark's School in Southborough, Mass, and then Harvard, Phi Beta Kappa before enlisting in the Marine Corps in 1918 where he was commissioned a second lieutenant a few days after World War I ended.
He returned to Harvard as a history instructor and assistant dean in 1925 and received a doctorate in 1930. In that year he was named headmaster of St. Mark's. Shortly after the United States entered World War II he joined the Army Air Corps and rose to colonel while serving in England, France and Germany.
In 1948 Mr. Parkman became executive secretary of the National Council of Independent Schools, a post he held until 1962 when the organization was succeeded by the National Association of Independent Schools, at which time he became the president.
Source: New York Times obit, july 18, 1990