When Disney was 16, he dropped out of school to join the Army but was rejected for being underage. Instead, he joined the Red Cross and was sent to France for a year to drive an ambulance. He moved back to the U.S. in 1919.

Walt Disney dropped out of McKinley High School in Chicago at the age of 16 primarily because he was deeply patriotic and desperate to contribute to the effort in World War I. Having always struggled with the rigid structure of traditional schooling—largely because he spent his nights working a grueling paper route for his father and his days doodling in his notebooks—Walt saw the war as an opportunity for adventure and a way to escape his father's strict authority. Because he was underage and could not join the regular Army, he forged the birth date on his application and joined the American Ambulance Corps, a division of the Red Cross. He spent a year in France driving an ambulance, which he famously covered in cartoons and drawings rather than camouflage. While he never returned to finish high school, his "dropout" status was motivated by a desire for real-world experience and service, a trait that would later define his relentless ambition as an entrepreneur. Interestingly, he eventually received several honorary high school diplomas and university degrees later in his legendary career.