[1] In 1992, Hassing made her film debut in the lead role of Nils Malmros' Pain of Love (Danish: Kærlighedens Smerte).
Malmros auditioned 362 actresses before choosing Hassing to play the role of an extremely emotional character named Kirsten, a manic-depressive student having an affair with her teacher.
Her qualities are very much my own: cheerfulness, the variety of emotions, vulnerability, but also the many mood swings, which for me never developed into actual depression.
In 1997, Hassing played the tender, uncomplicated character of Susanne in Lars Von Trier's Dogme film, The Idiots (Danish:Idioterne).
[6] From 2013 to 2024, Hassing was featured in the role of Therese Madsen in the hit television series Seaside Hotel.
[7] Hassing published Balance midt i livet in 2024 which was a humorous memoir and personal advice book about her experiences with menopause.