Ragnhildur studied at the Icelandic College of Art and Crafts from 1977 to 1981 and received her MFA from Carnegie Mellon University in Pittsburgh, USA, in 1987. In her art, she explores the body, perception, and emotion, and how the subjective and the objective are connected. She also creates public works, statues, and busts.

Her work is characterized by an experimental approach where material and meaning meet at the boundary between the personal and the public. She has long been drawn to what lies in between—between inside and outside, over and under, the visible and the intangible. This interest is central in her new works, the Mould Project, As without as within, where she explores how form emerges from absence as much as presence, and how impressions, cavities, and textures carry meaning. She sees the moulds and casts as a kind of laboratory—an incubator for ideas, emotions, and fragile states of becoming. The project examines existence through the lens of perception, memory, and the vulnerability of physical and emotional structures.

Ragnhildur works in a variety of media, including installations and reliefs, and her pieces are often noted for their emotional resonance and material sensitivity. She has held solo exhibitions and participated in group shows both in Iceland and abroad, and her works can be found in public spaces and art collections.