Troy Smith decided on "sole proprietorship" form of business. A sole proprietorship is a small business where there's really no legal distinction between the person who is the owner and the business itself.
Troy Smith opened his first drive-in business in Shawnee, Oklahoma in the early 1950s -- a root beer stand called Top Hat. In 1956 he added a partner (so his business became a "partnership" then.) Later he added many franchises (expanding the business further), and eventually his company became a publicly traded corporation. Oh, that corporation and chain of drive-in franchises is now called Sonic, which has been the name of the Smith-founded restaurant chain since 1959.
Troy Smith retired from managing the Sonic Corporation in 1983, and passed away in 2009, at age 87.