Jan de Witte was born in the Russian army encampment near Poltava on 8 July 1709, as a son of Jan de Witte (the Elder), a professional officer coming from a Dutch Protestant family from Dordrecht, at that time employed in the Russian army which waged war with Sweden. In 1718 Jan the Witte (the Elder) joined the army of Polish–Lithuanian Commonwealth, and took up residence in the town of Kamieniec in Podolia possessing the famous fortress. At that time he probably turned Catholic, he also married a local woman from a prominent noble family.