At 14 years old, Lassen won a silver medal in the women's 59 kg category at the 1995 Canada Winter Games in Grande Prairie, Alberta and still holds the Games record in the Clean & Jerk.

Lassen was a member of Team Canada as Athlete Mentor at the 2018 Winter Olympics in Pyeongchang, South Korea.

During the 2014 Commonwealth Games held in Glasgow, Lassen commentated on the weightlifting alongside David Goldstrom.

Lassen holds a Bachelor of Education from McGill University, with a speciality in English Second Language, and a Sports Performance degree from Camosun College.

She is former Executive Board member of the Canadian athletes' organization AthletesCAN, and Development and Education Commission for the International Weightlifting Federation and is currently the Athlete Representative on the Canada Games Council Sport Committee.