 In 1765, Hemert was granted citizenship as a merchant.Peter van Hemert and his half-brother Gysbert Behagen were at this poinjt made partners in their fath's company, whose name was at the same event changed to Joost van Hemert & Sønner (Joost van Hemert & Sons.Peter van Hemert was also active in the Danish Asia Company in which he owned up to 50 shares.