Sonja Laaser studied law at the HU Berlin and dramaturgy at the Hochschule für Schauspielkunst Ernst Busch, Berlin. She is a specialist lawyer for copyright and media law.

Until 2011 she was managing director of Ballhaus Ost and founded the art magazine "ArtiBerlin". During her law studies, she completed her legal clerkship at the Berlin Senate Department for Culture and Europe. These diverse stations help her to comprehensively understand and advise her clients: Her law firm, founded in 2015, focuses on advising cultural professionals in the areas of copyright, public procurement, grants, tax and corporate law, and artists' social insurance.

In addition to her activities as a lawyer and dramaturge, Sonja Laaser is increasingly involved in cultural policy. Together with Julia Wissert, she initiated and developed the anti-racism clause in 2018. In December 2020, she was appointed to the advisory board of the "Künstlersozialkasse". Since 2021, she has been involved in the research project "Systemcheck" of the Bundesverband Freie Darstellende Künste. Since January 2022, during her maternity leave, she has represented Lisa Jopt, president of the Genossenschaft Deutscher Bühnen-Angehöriger (GDBA), as the GDBA's collective bargaining representative in collective bargaining negotiations with the "Deutscher Bühnenverein".