Bennett was elected to the Ontario legislature in the 1971 provincial election, winning a convincing victory in Ottawa South. He served concurrently as MPP and on the Ottawa Board of Control before resigning as controller in August 1972 following the passing of a provincial law forbidding MPPs to serve on municipal councils at the same time. He was appointed as a Minister without portfolio in Davis's government on September 28, 1972, and was promoted to Minister of Industry and Tourism on January 15, 1973. He was re-elected by a reduced majority in the 1975 election, and again with a convincing majority in 1977. On January 21, 1978, he was named Minister of Housing.