She started working for CTV News in November 2005.
MacMillan started her broadcasting career as a reporter for MCTV in Sudbury, Ontario then for MCTV in North Bay, Ontario.
She earned both a bachelor's degree in political science from the University of Western Ontario and a graduate degree in journalism from Ryerson University's Graduate School of Journalism and graduated from Ancaster High School in 1989.
She had a health scare in 2012 when she was diagnosed with "a lot of blood clots in both lungs".
[2] She is also one of the fill-in anchors for CTV National News.