Munro was born in Hamilton, Ontario and was raised in Toronto, receiving a Bachelor of Arts degree from the University of Toronto. She worked as a teacher for twenty-five years before entering public life, and at one stage served as the Department Head of the York Region Board of Education. From 1992 to 1994, she was the President of the Durham—York Progressive Conservative Association.
Munro was first elected to the Ontario legislature in the 1995 provincial election, easily defeating incumbent New DemocratLarry O'Connor in Durham--York (many surrounding ridings also shifted from the NDP to the Tories in this cycle). She was re-elected in the redistributed riding of York North in the 1999 election (the Tory campaign was started in the community of Newmarket, in her riding). Munro was Parliamentary Assistant to the Premier from 1995 to 1998 and Government Whip from 1999 to 2001, but was never appointed to Cabinet.
The Tories lost the 2003 general election, although Munro was able to retain her seat by a reduced margin.
Munro had been, in the meantime, a contractor for erecting road-bed and railroad buildings for the Michigan Southern Railroad, having a train placed in his charge for transporting material.
Munro was appointed one of the Executive Committee, and was afterwards elected President of the society.
Munro has never connected himself with any religious denomination, but is a regular attendant of the Episcopal Church, contributing to its support.