Robert Jeffreys grew up in the Narrogin area and went to school at Wesley College in Perth. He trained at the National Institute of Dramatic Art (NIDA) in the late 1960s, graduating in 1971. After working for a period as an actor, Jeffreys returned to Western Australia and became a Drama and English teacher, teaching at a number of schools including, for seven years, at Carnarvon High School.
In 1990, Jeffreys worked as a real estate agent in Cottesloe but he subsequently returned to teaching. His plays have been produced at the Blue Room, Perth, by the Perth Theatre Company and on ABC Radio. Jeffreys has also run courses on writing for the stage.
In 2018, he released his debut novel, Man at the Window, the first in the Detective Cardilini series, set in Perth in the 1960s.