Mark was born and raised in Yellowknife, NWT. He served three terms on Yellowknife City Council from 2003 to 2012, was Deputy Mayor from 2006 to 2012, and was elected Mayor in 2012 and re-elected in 2015. During his time on Council, Mark chaired the City's Community Energy Planning Committee. From 2007 to 2017, he served as a member of the Federation of Canadian Municipalities' Green Municipal Fund Council. Mark joined the Arctic Energy Alliance as Executive Director in the fall of 2018.