Hall won a federal Senate seat for the Liberal Movement at the double dissolution 1974 election, after resigning his state seat, which sparked a Goyder by-election. At the Joint Sitting of Parliament, Hall supported the Labor government's three electoral reform Bills, citing his experience as South Australian Premier. During the 1975 Australian constitutional crisis, though opposed to the Whitlam government, Hall joined Labor (and independent Cleaver Bunton) in voting against the deferral of supply bills.