 In 1949, von Foerster started work at the University of Illinois at Urbana–Champaign at the electron tube laboratory of the Electrical Engineering Department, where he succeeded Joseph Tykociński-Tykociner.With his students he developed many innovative devices, including ultra-high-frequency electronics

He also worked on mathematical models of population dynamics and in 1959 published a model now called the "von Foerster equation", which is derivable from the principles of constant aging and conservation of mass.where