Riddle was born in
Narrabri,
New South Wales, the son of
pastoralist John Riddle. In 1889, aged 16, he joined the Narrabri branch of the
Bank of Australasia as a clerk. In 1915, Riddle joined the
Commonwealth Bank and was appointed the manager of the
Perth branch, where he remained until he transferred to
Sydney as the acting manager. In 1924, he was promoted to inspector and was transferred to manage the
Melbourne branch of the bank. ==Governor of the Commonwealth Bank==