Baptised in Bruges on 18 August 1623, Pieter Janssens was the son of the painter Gysbrecht Janssens Elinga and Catharine van Assené. His father, who was dean of the guild in Bruges and who may have trained him until his fourteenth year, died in 1637. Since Janssens's name does not appear in the guild registers, it appears that he left the city at the end of his training, or perhaps for its continuation. In 1653 he is documented in Rotterdam, where on 22 August, after the death of his first wife, Beatrix van der Mijlen, an inventory of their joint possessions was made. It suggests that they lived in modest circumstances. In addition to thirteen paintings that are not further identified, a violin is listed. This is the first indication of his activity as a musician, in which role he appears in later documents as well. On 16 March 1657 he enrolled in Amsterdam's citizen registry. In 1662 witnesses reported that he expelled a woman from his house in the Jodenbreestraat with the most shocking curses. He died before 24 September 1682, when his second wife, Jurina Bos, was identified as a widow in Amsterdam. He had at least four children, one of them from his first marriage. The slight oeuvre of this painter - who was only rediscovered in the late nineteenth century - encompasses roughly twenty paintings, equally divided between bourgeois interiors and still lifes. The interiors are similar to those of Pieter de Hooch, with whose works they were previously confused. The still lifes are considered to follow Willem Kalf.
