Pieter Cleasz. was born in Berchem, Flanders. He is mentioned in 1640 as being approximately forty-three years old, so his date of birth must have been in 1596 or 1597. In 1619 a Pieter Clasen joined the Antwerp guild, but it is not sure if this is the same person as Pieter Claesz.
In 1620/21 he moved to Haarlem, where in 1622 his son Nicolaes Berchem was born. Claesz. Is mentioned in Samuel Ampzing's Beschrijvinge ende lof der stad Haerlem, a description of Haarlem from 1628. Very little is know about his life. He was a member of the Guild of St. Luke in Haarlem and is registered as the teacher of his son in 1642. Cleaesz. died in December 1660 and was buried in Haarlem on January 1, 1661.
Only still lifes are known from Pieter Claesz. In the 1620s he developped together with Willem Claesz. Heda the „monochrome banketje“, a still life with very few objects and a very limited palette, making the handling of light and texture the prime means of expression. Almost all his work is signed with the monogram PC