She studied acting at the Södra Latin upper secondary school in Södermalm, which she credits with giving her the confidence to pursue her chosen career.

[12] On television, Mattsson made guest appearances on Two and a Half Men, Rules of Engagement, Legend of the Seeker, NCIS: Los Angeles and The Mentalist.

In 2012, Mattsson starred alongside Gary Oldman and Christian Slater in the action film, Guns, Girls and Gambling.

[17] Also in 2014, Mattsson appeared in two episodes of FX crime series, Fargo, and in 2015 played the female lead in the Hallmark Channel romantic comedy film, Win, Lose or Love.

[19] She appeared in a beaver costume in a Nespresso television commercial titled "Training Day" that also featured Danny DeVito and George Clooney in 2016.

[22] Also that year, Mattsson starred alongside her younger sister Sofia in the Lifetime television thriller film My Husband's Secret Wife.

[23] She later appeared in several other Lifetime movies: The Perfect One (2018), Neighborhood Watch (2018), Her Deadly Reflections (2019), Swipe Right, Run Left (2019), and Murder in the Vineyard (2020).