The son of an aristocratic Amsterdam merchant, Claes Cornelisz. Moeyaert became one of the most preeminent and prolific Dutch artists of his time. Details of his early artistic training are few, and his teachers are not known, but like many Amsterdam artists, he possibly visited Italy as part of his education.
Moeyaert's earliest style, simple and sometimes stiff, followed the manner of Adam Elsheimer and Pieter Lastman and focused on history painting. His biblical and mythological narratives featured powerful, three-dimensional figures in landscapes, both bathed in clear, warm light. During his early career, Moeyaert also made etchings that demonstrated his gift for integrating figural narratives in landscape settings. As early as 1618, he was praised in a poem about famous Amsterdam artists.
After Rembrandt Harmensz. van Rijn arrived in Amsterdam in 1632, Moeyart's style became more lively: he used more intense color and more varied motifs and created more animated figures. He also followed Rembrandt in using red chalk. Always making fully elaborated preparatory drawings, he worked on festival decorations, religious pieces, and a few group portraits. Moeyaert taught Nicolaes Berchem and remained an influential figure for the next generation of artists.