Hewitt was born and raised in Toronto, then moved to Vancouver in 1962 where he attained his accounting designation.[2] He settled in the Okanagan in 1967, and worked as a manager at the Penticton and District Credit Union; he was elected Penticton alderman in 1969.[2]
He ran as a Social Credit candidate in the 1975 provincial election, and was elected member of the Legislative Assembly (MLA) for Boundary-Similkameen.[3]: 323 Initially without a cabinet post, he was named Minister of Agriculture in October 1976 by Premier Bill Bennett, then served as Minister of Energy, Mines and Petroleum Resources from December 1978 to November 1979.[4] After winning re-election in May 1979,[3]: 333 he regained the agriculture portfolio, which was re-titled to Minister of Agriculture and Food in August 1980.[4] He was re-assigned as Minister of Consumer and Corporate Affairs in August 1982, and kept that post following his re-election in 1983 before becoming Minister of Education in February 1986.[3]: 341 [4]
Hewitt was named Minister of Agriculture and Fisheries after Bill Vander Zalm became premier in August 1986.[5] Boundary-Similkameen became a two-member district in that October's election; Hewitt was re-elected there alongside Ivan Messmer.[6] He was not given a cabinet position,[5] and resigned as MLA in December 1987 over disagreements with Vander Zalm;[6][7] he subsequently served seven years as chairman of the Farm Credit Corporation.[2] Although retired from elected politics, Hewitt actively campaigned against the province's 2009 electoral reform referendum.[8]
He met Dorothy Barber when she worked on his campaign in 1979;[2] they were married in 1980.[9] He has four children with his first wife Sheila.[9][10]