Born in Stockholm, Sissi Westerberg obtained her master's degree in metal craft from the University of Arts, Crafts and Design (Konstfack) in 2002, specialising in conceptual jewellery art. She also studied at the Bezalel Academy of Arts in Jerusalem. In her artistic works, Sissi Westerberg often explores the relationship between the body, ornamentation, and phenomena in our surroundings.

In 2004, Sissi Westerberg was one of ten female designers invited to participate in a tribute collection to Estrid Ericson for Svenskt Tenn's 80th anniversary. Her contribution to the collection was the now-classic Flow candleholder. Since 2009, Sissi Westerberg has been a co-director of Rejmyre Art Lab in Rejmyre, and she also works as a teacher at the Rhode Island School of Design in the USA.