Theodor Seuss Geisel was born in Springfield, Massachusetts to German-American parents. He attended public schools and then went to Dartmouth College, where he became editor of the Dartmouth Jack-O-Lantern. When he was barred from all extracurricular activities, he continued to write for the paper using the pseudonym "Seuss." After he graduated, he became a contributor to the magazine The Judge, and began to sign his work as "Dr. Seuss."

He attended Lincoln College, Oxford to earn a D.Phil in literature but married Helen Palmer in 1927 and returned to the United States without earning the degree. He published humorous articles and illustrations in The Judge, The Saturday Evening Post, Life, Vanity Fair, and Liberty and supported himself and his wife through the Great Depression with commercial illustrations for companies like General Electric and NBC.

In 1937, returning from an ocean voyage to Europe, he wrote his first book, And to Think That I Saw It on Mulberry Street. During World War II, he created political cartoons and became an editorial cartoonist for the left-wing New York City newspaper, PM. His political cartoons were later published in Dr. Seuss Goes to War. He joined the Animation Department of the First Motion Picture Unit of the U.S. Army Air Forces, where he wrote propaganda and training films.

After the war, he moved to La Jolla, California and returned to writing and illustrating children's books. In 1954, inspired by an article in Life magazine on the dullness of children's books, Geisel wrote The Cat in the Hat. Over his career, Geisel wrote over 60 children's books under the pseudonym "Dr. Seuss," "Theo. LeSieg," and "Rosetta Stone." He also wrote two books for adults: The Seven Lady Godivas and Oh, The Places You'll Go! Geisel died in La Jolla, California in 1991.

He received two Primetime Emmy Awards and a Pulitzer Prize Special Citation in 1984. His birthday, March 2, is celebrated as National Read Across America Day.