[2] His grandfather was Theobald Butler Barrett, Member of the Canadian Parliament for Norfolk from 1945 to 1949.

He later worked as a teacher of High School agriculture, and has been a partner in Farmleigh Farms since 1980.

[6] Barrett supported Jim Flaherty's unsuccessful bid to succeed Ernie Eves as leader of the Progressive Conservative Party in 2004.

[8][9] Barrett served as the Parliamentary Assistant to the Minister of Natural Resources and Forestry under Premier Doug Ford.

[11] When he announced his retirement, his longtime executive assistant Bobbi Ann Brady planned to run for the nomination to replace him as the PC candidate, but after the party's central office directly appointed Haldimand County mayor Ken Hewitt as its new candidate without consulting the local electoral district association,[12] Brady opted to run against Hewitt as an independent, with Barrett's endorsement and participation in her campaign.