Upon returning to America, Geisel decided to pursue cartooning full-time, and his articles and illustrations were published in numerous magazines, including LIFE and Vanity Fair. A cartoon that he published in the July 1927 issue of The Saturday Evening Post, his first using the pen name "Seuss," landed him a staff position at the New York weekly Judge. He then worked for Standard Oil in the advertising department, where he spent the next 15 years. His ad for Flit, a common insecticide, became nationally famous.