Mikkelson grew up in
St. Albert, Alberta, and represented Team Alberta at the 2003 Canada Winter Games in Bathurst and Campbellton, New Brunswick, as the Alberta team finished in seventh position.
Wisconsin Badgers In 2007, Mikkelson tied for 11th in the NCAA with 42 points in 34 games and tied for sixth with 32 assists. Among defencemen, she was second in the country during the regular season with 1.24 points per game and ninth overall with .94 assists per game. During the 2006–07 NCAA season, she was part of the Wisconsin defence that allowed a nation's best 0.94 goals per game and 15 shutouts, a school record. In the WCHA, she led all defencemen with 33 points in 28 league games and was fifth overall. She tied for second in the league with 24 assists.
Hockey Canada Mikkelson made her Team Canada debut with the National Women's Team at the 2007 Fall Festival. She appeared in her first IIHF World Women's Championship in 2008. In the gold medal game of the 2010 Four Nations Cup, she had a goal and an assist for Canada. With 1:49 left in the second period, she scored to tie the game and force overtime. In a game versus Russia at the
2012 IIHF Women's World Championship, she registered three assists in a 14–1 victory. She won a gold medal during the
2010 Winter Olympics and was named to the
2014 Winter Olympics roster for Canada, when she again won a gold medal. She won a silver medal at the
2018 Winter Olympics.
CWHL Prior to being selected third overall in the
2011 Draft of the
Canadian Women's Hockey League, Mikkelson played with the
Edmonton Chimos of the
Western Women's Hockey League (WWHL). She was selected by the Alberta Honeybadgers, a team later renamed as Team Alberta CWHL but eventually called the
Calgary Inferno. Appearing in the 2016
Clarkson Cup, she registered one assist as the Inferno emerged victorious in the 8–3 final game win. She was one of two captains for Team Blue in the
3rd CWHL All-Star Game, the first time that one team in the CWHL All-Star Game had two captains. ==Awards and honours==