We have no definite knowledge of his training, and but scant information as to the course of his life. According to the Netherlands Institute for Art History, he was a pupil of Cornelis van der Voort. The landscape painter Jacob Isaakszoon van Ruisdael painted a landscape as a background to one of his group portraits.
In the 1640s, de Keyser received very few painting commissions, and was forced to seek income elsewhere.
He owned a basalt business from 1640 until 1654, when he returned to painting.