They lived at Thorngate, then "Willyama", Medindie, and he was educated in Victoria at Geelong Grammar School before returning to South Australia to attend the University of Adelaide and Roseworthy College.

He became a grazier and cattle breeder, and served in the Royal Australian Air Force from 1942 to 1945 during the Second World War.

In 1959, Giles was elected to a Southern district seat in the Legislative Council as a Liberal and Country League member.

[1] In 1964, he resigned to contest the by-election for the Australian House of Representatives seat of Angas, caused by the resignation of Alec Downer; he won the seat as a candidate for the LCL's federal counterpart, the Liberal Party.

He then followed most of his constituents into neighboring Wakefield, defeating fellow Liberal Bert Kelly for preselection.