Paid his way through Chicago Art Insitute by playing clarinet in Dixieland and Chicago-style bands. When he heard a 12-year-old Benny Goodman outplay him, he opted to concentrate on art. Moving to New York, he gained assignments with Pictorial Review, American Magazine, Saturday Evening Post, Collier's. Ads for Tydol/Veedol Gasoline (a WW2 billboard for this company won an Outoor Advertising award), Roma Wines, Ruppert Beer, Old Gold. For the last, he originated the dancing Old Gold packs for TV as he moved from print assignments to the new medium of television. Co-authored, with Neil O'Brien, "Television Advertising," 1958. Sometimes signed his works "Ian Mansfield."

Special thanks to Bruce Agnew, Clark's son,
for the biographical info.