When a youth he distinguished himself by painting homely scenes, in which he reproduced articles of furniture, cooking utensils, etc., with marvellous fidelity, but he afterwards cultivated historical painting. Several of his best works, altar-pieces in various churches, were destroyed in the religious wars of the Netherlands.

An excellent specimen of his style on a small scale, a picture of the crucifixion, may be seen in the Antwerp Museum. Aertszen was a member of the Academy of St Luke, in whose books he is entered as "Langhe Peter, schilder". Three of his sons ( Aert Pietersz , Dirck Pieters und Pieter Pietersz) attained to some note as painters.