He was born in Danzig. He studied at the University of Marburg and then at the University of Leiden, where he took a law degree. He then moved to Utrecht, and married. He became a Fellow of the Royal Society in 1735.
Sellius was appointed to chairs of law, at the University of Göttingen, and at the University of Halle. He taught experimental physics at Halle, but money troubles caused him to move away. A valuable library was auctioned off in 1737.
In Paris Sellius took on translation work, in particular of the Cyclopaedia of Ephraim Chambers. This project came to a brusque end, when the prospective publisher André Le Breton rejected the draft translation of Sellius and John Mills, leading to a violent clash and litigation. It did clear the way for the Encyclopédie of Denis Diderot and Jean le Rond d'Alembert, conceived around 1750 as a new adaptation of the work of Chambers, though subsequently taking its own course.
- Philipp Blom (2004), Encyclopédie: The triumph of reason in an unreasonable age, Fourth Estate
- Blom, p. 36.
- John Lough (1971). The Encyclopédie. Slatkine. p. 8. ISBN 978-2-05-101046-7. Retrieved 10 December 2012.
- (French)Joseph-Marie Quérard (1838). La France littéraire ou dictionnaire bibliographique des savants, historiens et gens de lettres de la France, ainsi que les littérateurs étrangers qui ont écrit en français, plus particulièrement: pendant les XVIIIè et XIXè siècles. Firmin Didot père et fils. p. 40. Retrieved 10 December 2012.
- J. L. Heilbron (1982). Elemnt Early Mod Phys. University of California Press. p. 140. ISBN 978-0-520-04555-2. Retrieved 10 December 2012.
- (German) Gustav Körting (1871). Altfranzoesische uebersetzung der Remedia amoris des Ovid: (ein theil des allegorisch-didactischen epos "Les échecs amoureux"). Fues. p. iv note. Retrieved 10 December 2012.
- Blom, p. 38.