Red-cheeked and Rubenesque, Sundblom’s version of Santa, originally based on a retired salesman who happened to be the illustrator’s friend, became wildly popular, and endures today.

Red velvet suit, white fur trim, tall black boots, cozy (if not indulgent) pom-pom hat. Santa Claus’ uniform may have some variations, from Tim Allen’s off-duty outfits in “The Santa Clause ...