Koets became a member of the Haarlem Guild of St. Luke in 1654 as a vinder.
[1] He collaboated with Haarlem still life painters Pieter Claesz and Jan Jansz van de Velde.
[2] He himself was influenced by Floris van Dyck and in turn influenced Floris van Schooten.
[2] He became the teacher of his son, the later painter Andries Koets.
[2] He is not to be confused with the later painter Roelof Koets of Zwolle, who painted mostly portraits.