Career
He was elected as an Ulster Unionist Party Member of Parliament for Belfast East at the 1959 by-election. He held the seat until the February 1974 United Kingdom general election, when he lost standing as a Pro-Assembly Unionist to the Vanguard leader William Craig. At the October 1974 United Kingdom general election, McMaster stood unsuccessfully as an "Independent Ulster Unionist" candidate in Belfast South, taking third place with 9.8% of the vote.