Following World War II, Troy N. Smith Sr., Sonic’s founder, returned to his hometown of Seminole, Oklahoma, where he became employed as a milkman. In 1953, Smith went in with a business partner to purchase a five-acre parcel of land that had a log house and a walk-up root beer stand, already named the Top Hat. The two men continued with the operation of the root beer stand and converted the log house into a steak restaurant. After realizing that the stand was averaging $700 a week in the sale of root beer, hamburgers and hot dogs, Smith decided to focus on the more-profitable root beer stand. He also bought out his business partner. Upon learning that the Top Hat name was already trademarked, Smith and Pappe changed the name to Sonic in 1959. The new name worked with their existing slogan, "Service with the Speed of Sound".
As of August 31, 2011, there were 3,561 restaurants in 43 U.S. states, serving approximately 3 million customers per day. In 2011, it was ranked 10th in QSR Magazine
Sonic is a member of the hamburger segment of fast food restaurants, so the menu consists of some classic fast food items, such as hamburgers, and french fries as well as other "carnival-like" fare such as onion rings, corndogs, and hotdogs. Other items that are special to Sonic’s menu include Breakfast Toaster sandwiches (made with Texas toast instead of the typical bun), Cheddar Peppers, and new Flatmelts. Drink options include soft drinks, slushes and milkshake. Customers can combine various drinks and flavors to create thousands of possible drink combinations.