dehaven was born in 1895 in brooklyn, new york. his father was a steel worker and inventor. he attended fessenden school in west newton, massachusetts from 1906 to 1909 before attending the hill school in pottstown, pennsylvania from 1909 to 1914. following graduation dehaven attended cornell university from 1914 to 1915, and columbia university from 1915 to 1916. he tried to join the us army air corps in 1916, but was rejected. he joined the royal flying corps canada in toronto, ontario, canada.