After studying at the Academy of Fine Arts in København, Niels Knudsen became known at a fairly young age for his design of a single-story model house for a competition of the newspaper Politiken. His designs were modern and functionalist. His most important project, however, was the central registry of Danish architecture. Since 1954 he was the responsible architect for urban planning of the municipality of Frederiksberg, part of the capital region of København (Copenhagen). In addition, he worked as an artist with textiles.