Born into a family of painters, he was first trained by his father, Jacob Cornelisz van Oostsanen. Jacobsz. The Mannerist style of fellow Amsterdam painter Jan van Scorel profoundly influenced him. His painting The Crossbowmen (1529) was his most important piece. It was the first militia portrait in Dutch history.^[1] He married Marritgen Gerritsdr. in 1550, and they had two children, Maria Dircksdr. and Jacob Dircksz. Jacob later became a painter as well.^[2] Не painted two earlier group portraits of civic guards, which hang in the State Hermitage in Saint-Petersburg.

• Entry in Amsterdam Rijksmuseum catalogue Archived 10 October 2012 at the Wayback Machine