[1] He was educated at Geelong Grammar School, after which he was an executive trainee at a civil engineering company in Melbourne.
After his national service, he moved to Papua New Guinea, where he worked on a coffee plantation and in a timber milling company.
He was appointed as overseer of the "Nareen" property in Western Victoria, then owned by future Prime Minister Malcolm Fraser.
[3] He entered politics as a councillor on the Yea Shire Council in 1970, also marrying Prudence Manifold that year.
Plowman lost his seat at the 1982 state election, and returned to farming for a time until regaining Evelyn in 1985.