Career
During her time in office she served in the Executive Council of Alberta as Minister of Culture under the Peter Lougheed government. LeMessurier ran for a seat to the Alberta Legislature in the 1979 Alberta general election. After the election Premier Peter Lougheed appointed her to be the Minister of Culture.
LeMessurier ran for re-election in the 1982 Alberta general election.
She increased her popular vote but also faced stiff competition from challenging candidate Iain Taylor of the New Democratic party. On June 12, 1985 LeMessurier declared Alberta Government House a provincial historical site.
She kept her portfolio after Don Getty became premier in November 1985. She ran for a third term in the 1986 general election but was defeated in a hotly contested race by William Roberts.
After her defeat from office, she was appointed by the Government of Alberta as the Agent General of Alberta.
She spent six years in that position before returning to Alberta.