With the artists Herman Berserik, Jan van Heel, Willem Hussem and Jaap Nanninga he participated in the Verve group,[2] which they founded in 1951 and dissolved in 1957.

From 1958 to 1971, he was a lecturer in figure drawing at the Royal Academy of Art, The Hague.

In 1971, he moved to Rotterdam, and started a studio in the south of France, where he worked alternately until 2010.

[2] Westerik was awarded the Jacob Maris Prize three times: in 1951 and 1955 for painting and in 1953 for drawing.

[2] In 1999, he was appointed Knight of the Order of the Netherlands Lion[4] and in 2005 an honorary member of Pulchri Studio.