Oakley was born in Auckland, North Island, New Zealand on 21 August 1943 and had a regular suburban upbringing.
After leaving Auckland Grammar School, he studied languages in New Zealand, before he moved to England where he started his career in theatre.
His other notable roles include The Sullivans appearing in both the television series and film version as Major.
Oakley appeared in feature film roles including in 1977 in his native New Zealand in the movie Sleeping Dogs starring Sam Neill, and in Australia in Sara Dane, Women of the Sun, TheFar Country, Travelling North .The Last of the Ryans My Year Without Sex but has also appeared in numerous telemovies and mini-series including the 12-part serial The Damnation of Harvey McHugh.
He featured in the stage productions of My Fair Lady, The NightWatchman, Circle Mirror Transformation by Annie Baker, and The Golden Dragon by contemporary German playwright Roland Schimmelpfennig.