Jan Voorberg called himself an autodidact. Trained as an architectural draftsman, he established himself as an independent architect in 1972. From 1972-1973 he was assistant to J.B. Bakema at TU Delft, gave classes on architecture to do-it-yourselfers, gave lectures, guest lectures and designed projects, including for PRO The Hague. He had a very extensive architecture library and in his lectures and lectures used the slides he made during his study trips in Europe and outside Europe, including Greece, Italy and Egypt. In his lectures and also in his work, the aspects of light, color and sightlines in architecture kept recurring. A famous statement by Voorberg was: "It is not only about removing the causes of disease, cold, hunger, noise and insecurity. A sense of dignity, of pride and of affection for and of one's surroundings are more important for human happiness. These needs are satisfied not only by good sanitation, heating and insulation, but also by well-proportioned spaces, rich entry of daylight, matched colors, visual order and harmony. Jan Voorberg took the initiative to support Rem Koolhaas's design for the renovation of De Tweede Kamer. From this contact resulted the collaboration with the Office for Metropolitan Architecture (OMA) in Rotterdam. From this collaboration came three designs for which Jan Voorberg was primarily responsible. The urban design for the IJ-plein in Amsterdam-Noord came about after frequent rounds of consultation with local residents in the early 1980s. The design reflected his idea of "village-like urbanity," thus accommodating the conflicting wishes of residents. The Nederlands Danstheater was to have its own building near the Circustheater in Scheveningen. The design for this was ready when Jan Voorberg died. In both designs, sightlines for residents and visitors, respectively, played an essential role in the design of the district and hall. In the competition for the Parc de la Villette in 1983, Voorberg made an extensive tree plan. The entry won second prize. After this project, Voorberg also increasingly developed into a landscape architect. His last trip in October 1983, with the commission for the Danstheater to be built in his pocket, was to Brazil. Before meeting in Rio de Janeiro with Burle-Marx (chairman jury Parc de la Villette) and Oscar Niemeijer, he visited Reidy's urban plan Predegulho whose garden was designed by Burle-Marx. He was photographing the buildings in the plan with his Leica. Here he was ambushed and shot. As Ole Bouman put it in 2012, "Jan Voorberg died in armor" to which Herman Hertzberger had the following response, "if only he had worn armor..." .