Allerton Cushman attended the Hackley School in Tarrytown, New York and then Harvard, where he rowed crew. In World War II, he was a 2nd lieutenant in field artillery, serving in North Africa, where he earned a Silver Star for gallantry. After the war he started a career with Morgan Stanley in New York in investments but left that position to move to Texas where he worked for several investment firms. In the early 1950s, Cushman re-married (his first marriage ended in divorce) and he and his wife moved to Phoenix where they operated a cattle ranch there and also one in British Columbia. In 1978, Cushman sailed across the Atlantic with his friend, Philip Weld from Harvard, who went on to win the 1980 Observer Single-Handed Transatlantic Race.