It is only after moving to the workshop of Anthony van Dyck that Thijs learned portrait and history painting and started copying the great masters.
[4] After leaving Coques' workshop Thijs started out on a career that was successful despite the prevailing dire economic situation in Antwerp.
He obtained many commissions for altarpieces in churches in Flanders and Brabant as well as for portraits, and allegorical and mythological paintings from patrons in both the Southern Netherlands and the Dutch Republic.
From 1647 onwards, he became a portrait painter as well as a tapestry designer for Archduke Leopold Wilhelm of Austria, then the Governor of the Southern Netherlands, while at the same time taking on commissions from the rival House of Orange in The Hague.
[6] Pieter Thijs produced allegorical and mythological compositions for the courts of the Southern Netherlands and the Dutch Republic as well as the local churches and monasteries.
Thijs, on the other hand, applied the paint more tightly and thickly, and his figures express their emotions with more decorum and contained theatricality.
Other possible influences are the works of slightly senior painters such as Thomas Willeboirts Bosschaert and Gonzales Coques who were both early followers of van Dyck as well as Thijs' predecessors at the courts of Brussels and The Hague.
[3] He showed himself to be an eclectic painter who did not strive for originality but adapted and borrowed from the styles of other artists where he felt the commission demanded it.
He gained in particular a reputation for large family portraits, a genre made popular by his teacher Anthony van Dyck.
[6] His portraits followed the style of van Dyck in the eloquence of the hands and the meticulous execution of the reflections on the shimmering fabric.
In this mature period from the 1660s onwards, Pieter Thijs usually relied on pyramidal, symmetrical compositions and he painted his female figures draped in tunics tied at the waist and wearing garments with folds in V-form.
[2][10] Pieter Boel probably also painted the still life and parrot in Thijs' Portrait of Philips van de Werve and His Wife.
[12] In the 1650s, Pieter Thijs worked with Thomas Willeboirts Bosschaert, Jan Brueghel the Younger and Adriaen van Utrecht on the cartoons for two series of tapestries for Archduke Leopold Wilhelm, with the titles Day and Night and The Months.