Initially self-taught, Cooper was introduced by his uncle to famous sporting artist, Ben Marshall. From this time on, Marshall offered Cooper instruction, studio space and introductions to interested patrons, a role Cooper later went on to provide for young aspiring painters once he had established his own career. From 1811, Cooper became a prolific lifetime contributor of illustrations to The Sporting Magazine. He began to specialise in battle scenes, many of which were exhibited at the Royal Academy. In 1820, on the strength of this work, he was given full honorary membership of this institution, but he continued to produce many sporting paintings too.