McCorkle Westerburg & Thornton, P.C., founded in 1972 as the partnership of McCorkle & Westerburg, was first located in a two-room suite in the Texas Bank & Trust Building (later the Main Bank Building).Tom McCorkle, from 1971 a sole practitioner in criminal law, was joined in August, 1972, by Rob Westerburg, who was establishing his civil litigation practice. The firm offered general legal services, concentrating in the areas of criminal defense, family law, personal injury, and business matters.

The firm remained in the Main Bank Building until 1978 when it moved to the Katy Building in the Historic District of downtown Dallas. Situated across the street from the Kennedy Memorial, the historic Katy Building was the firm's home for 20 years. Over the years, the practice grew to include the areas of probate, real estate, and professional ethics and discipline.

In 1994, Steve Thorntonjoined the firm as an associate, enhancing its personal injury practice. Steve became a full partner in 1998, the same year the firm moved its office to the famed Turtle Creek area of Dallas and became McCorkle Westerburg & Thornton, P.C.