Sonja Gerhardt was born in Berlin on April 2, 1989. For eleven years, she was a member of the children ensemble of the Friedrichstadt-Palast. She made her TV debut in the soap opera "Schmetterlinge im Bauch" (2006-2007), playing the role of an awkward teenage girl over the course of 120 episodes. She got her first leading role in a theatrical release with "Sommer" ("Summer", 2008), and went on to star in the acclaimed made-for-TV drama "Sklaven und Herren" and in Vivian Naefe's box office success "Die wilden Hühner und das Leben" ("The Wild Chicks and Life", 2009).

Sonja Gerhardt next appeared in a string of TV productions, including the disaster movie "Vulkan" (2009) and the action capers "Die Jagd nach der heiligen Lanze" (2010) and "Die Jagd nach dem Bernsteinzimmer" (2012). She also played the girlfriend of a drug addict in Vivian Naefe's "Mein eigen Fleisch und Blut" (2011), and a college student bent on marrying her just recently found boyfriend in the comedy "Heiraten ist auch keine Lösung" (2012).

After being one of the leads in the TV adaptation of the fairy tale "Schneeweißchen und Rosenrot" (2012), Gerhardt joined the ensemble cast of the TV production "Mittlere Reife" (2012), which later was awarded the Hessische Filmpreis.

Following a supporting role in the box office hit "Türkisch für Anfänger" (2012), Sonja Gerhardt guest-starred in a three-episode-arch of the TV series "Mordshunger - Verbrechen und andere Delikatessen". From 2014 on, she focused on her movie career with leading roles in the horror film "Tape 13" and "Dessau Dancers" (2014), which revolves around a breakdance crew in East-Germany. In 2015, she played the older sister of a young drug addict in the drama "Sin & Illy still alive".