He is the first coach of the women’s national team to be employed full time by the Finnish Ice Hockey Association.

[1] Mustonen has served as head coach of the women‘s national team since 2014 and is under contract through the 2022 Winter Olympics in Beijing.

During Mustonen's second season with the team, Kärpät forward Matti Veivo was paralyzed after a severe injury sustained in an October match against Kalajoen Junkkarit.

Mustonen and the team were deeply affected by Veivo‘s injury but were not permitted to delay or reschedule any matches and struggled as the season wore on.

Mustonen was offered the Finnish women's national ice hockey team head coaching position at the suggestion of Aravirta, who had turned down the position in favor of retirement when Kalervo Kummola, chairman of the Finnish Ice Hockey Association, offered it in Spring 2014.

Mustonen began in Summer 2014, despite having no previous women‘s coaching experience, and inherited a team that had been kept off the medal podium three consecutive times, ranking fourth at both the 2012 and 2013 IIHF Women's World Championships and fifth at the 2014 Winter Olympics, the lowest Olympic ranking in team history.

Finland saw success in the first major international tournament with Mustonen at the helm, the 2015 IIHF Women's World Championship, breaking its podium drought with a 4–1 win against Russia in the bronze medal game.