Just van Rossum graduated in 1989 at the Royal Academy of Fine Arts in The Hague, where he studied with Gerrit Noordzij. His collaborations with Erik van Blokland under the name LettError became well known and their FF Beowolf typeface has been included in the permanent collection of the MoMa in New York. His FF Lefthand typeface is as ubiquitous now as it was when it came out in 1991. He co-wrote RoboFog with Petr van Blokland in the mid-ninetees, which can be seen as a prerunner of RoboFont, and has been a very influential type design tool due to its groundbreaking scriptability with the Python programming language. He is the original author of the the Python-based FontTools/TTX library, which provides powerful and unique ways to build and edit OpenType fonts.
Just teaches type design and programming at the Royal Academy of Fine Arts (KABK) in The Hague, both in the regular graphic design course as well as in the Type & Media master program.