He started his career as an architect and worked for Jan Wils and Berlage.

As a designer, Zwart was well known because of his work for both the Nederlandse Kabelfabriek Delft (the Dutch Cable Factory in Delft) and the Dutch Postal Telegraph and Telephone, and as a pioneer of modern typography. He did not adhere to traditional typography rules, but used the basic principles of constructivism and "De Stijl" in his commercial work. His work can be recognized by its primary colors, geometrical shapes, repeated word patterns and an early use of photomontage.

He created a total of 275 designs in 10 years for the NKF Company, almost all typographical works. He resigned in 1933 to become an interior, industrial and furniture designer.

Piet Zwart died at the age of 92 in 1977. The Piet Zwart Institute of the Willem de Kooning Academy Rotterdam - the same art school of which he was a professor in the 1920s - is named after him.