Pioneering American political cartoonist and illustrator Thomas Nast — who was active during the mid to late 19th century, and particularly during the period of the American Civil War — was instrumental in the creation of the contemporary image of Santa Claus.
Though I often credit the later illustrations of J.C. Leyendecker with fully fleshing out the modern version of the character as we now know him (prior to similar interpretations by Norman Rockwell, N.C. Wyeth and Haddon Sundblom), Nast pretty well established the general characteristics we associate with the Jolly One, down to the fur-trimmed suit, belt, boots, cap and sack of toys.
These were based largely on descriptions in the poem A Visit from St. Nicholas — published anonymously in 1923, later attributed to Clement Clarke Moore — better known as “The Night Before Christmas”.
Nast portrayed Santa Claus in a number of illustrations, many of which appeared in the pages of Harper’s Weekly. The image above, top, is well known and widely reproduced; others are less frequently seen. As far as I know, these were all in black and white, and any color versions of them were applied by later hands.
Nast’s Santa — developed at a time when Christmas was celebrated in the US, but was not yet a national holiday — is a bit less innocently jolly than current interpretations, slightly odd and even a bit devilish and creepy at times.