Karlsson engaged in music from an early age, though not always at a professional level. She has been singing and dancing almost her entire life, and at the age of 15, she won a competition called The Smallest Schlager Competition in the World. Despite her musical successes, she continued to focus on her other passion, handball, playing in Finland’s top division with Siuntio IF. As a female handball player, Karlsson has highlighted issues of sexist comments in the sports world.
On the Finland-Swedish radio channel Yle X3M, she created the program Stiftelsen together with Frida Lindholm. They called themselves “Frillan” and “Prillan” and since August 2014, also produced the podcast Frillan & Prillan OFF AIR. Karlsson left the radio channel in June 2018.