Employed in London as an illustrator and caricaturist, Sarg became an active part of the city’s advertising community. From 1912 to 1914, he designed posters for the Electric Underground Railway Company and became a member of the London Sketch Club, meeting other prominent poster designers of the time. Arriving in New York, Sarg continued his career, easily fitting in with fellow illustrators, writers, and performers who formed the Dutch Treat Club, which boasted among its membership such notable figures of the time as Robert Benchley, Ogden Nash, Jerome Kern, and Norman Rockwell. Elected to membership in the Salmagundi Club, he joined the entertainment committee and performed puppet plays at the venerable arts institution.

Besides producing illustrations for leading publications such as The New York Times, The Saturday Evening Post, Collier’s, Vanity Fair, and others, Sarg’s Up & Down New York, first published in 1926, offered readers an overview of New York City of the 1920s, featuring dynamic and vibrant illustrations of the city’s landmarks and subway system. He also created engaging, illustrated maps, notably for Nantucket and the 1933 Chicago World’s Fair, and he designed extensively for the New York World’s Fair in 1939, creating the fair’s official pictorial map.

As if Sarg’s success as an illustrator was not enough to secure his place in history, he also distinguished himself by staging such acclaimed marionette performances as The Three Wishes and The Rose and the Ring in New York City’s Flatiron Building as early as 1917. In the 1920s and 1930s, in the height of his popularity, Sarg’s emphasis on movement in art and his puppetry skills were instrumental in many of his ventures, including the creation of animated cartoons, mechanical figures for window displays, and the inaugural Thanksgiving Day parade balloon for Macy’s Department store (1927), among others. During this time, Sarg wrote and/or illustrated almost thirty picture books, some created with moveable parts, often featuring animal characters to entertain and educate his young readers.