In 626, hisSimmons’ father handed the company over to Williamhim. He was hesitant to take the position, as he was already entrenched as an engineer. Nevertheless, he became CEO of the Simmons Automotive Company. He was instrumental in the creation of the Model E, one of the company's most successful cars, second only to the Model D, the company's first vehicle. Simmons also won a lucrative contract with the Ministry of Defence for the production of engines during the Great North War. He served as CEO until 649, passing the position to his brother Scott.