Michael Byrne O'Reilly immigrated to America in 1849, escaping from the hard times of the potato famine, which struck Ireland in 1845-46. Settling in St. Louis, he worked his way through school to earn a law degree, and then pursued a career as a title examiner. His son, Charles Francis O'Reilly, attended college in St. Louis and went to work in 1914 as a traveling salesman for Fred Campbell Auto Supply in St. Louis. By 1924, Charles had become familiar with the Springfield area, having traveled by train to sell auto parts throughout the territory. He recognized the region as an area of growth and opportunity and asked to be transferred there. By 1932, he had become manager of Link Motor Supply in Springfield. One of his sons, Charles H. (Chub) O'Reilly, had also joined the company. Together they provided the leadership and management that made Link the predominant auto parts store in the area.

In 1957, Link planned a reorganization, which would have included the retirement of 72-year-old Charles F. O'Reilly, and the transfer of C. H. O'Reilly to Kansas City. Since neither agreed with these plans, they made the decision to form their own company, O'Reilly Automotive, Inc. They started in November of 1957 with one store and 13 employees at 403 Sherman in Springfield. Their sales totaled $700,000 in 1958, their first full year of business. Due to the hard work and ability of the original employees, several of whom were stockholders in the company, the business grew and prospered from it's very first year.

By 1961, the company's volume had reached $1.3 million;a figure which indicates the combined volume of O'Reilly Automotive and Ozark Automotive Distributors, a division which had been formed to serve independent automotive jobbers in the area. In March of 1975, annual sales volume had risen to $7 million and a modern, 52,000-square-foot facility at 233 S. Patterson was built for the O'Reilly/Ozark warehouse operation. By that time, the company had a total of nine stores, all located in the southwest Missouri area.

On April 23, 1993, the company completed an Initial Public Offering of common stock, and it now trades in the NASDAQ system under the symbol ORLY. In addition to stock for sale to the general public, the company also has a stock purchase plan to enable as many team members as possible to own stock in the company.

On January 30, 1998, O'Reilly merged with Hi/LO Auto Supply, adding 190 auto parts stores in Texas, and Louisiana, as well as a distribution center in Houston, Texas. The Hi/LO acquisition made O'Reilly one of the top ten auto parts chains in the country.

On April 25, 2000, O'Reilly Auto Parts announces the purchase of KarPro Auto Parts, which includes 66,000 square foot distribution center In Little Rock, Arkansas and 14 KarPro stores.

On October 1, 2001, O'Reilly purchased Mid-State Automotive Distributors, Inc., adding 85 auto parts stores in Alabama, Florida, Georgia, Indiana, Kentucky, Mississippi and Tennessee as well as four distribution centers in Nashville, Knoxville, Chattanooga and Pensacola. The acquisition made O'Reilly one of the top five auto parts chains in the country. O'Reilly added its 11th distribution center in Atlanta, Georgia in March 2005.

On May 2, 2005, O'Reilly purchased Midwest Automotive Distributors, Inc., adding 71 retail locations in Minnesota, Montana, North Dakota, South Dakota, Wisconsin, and Wyoming and two distribution centers located in St. Paul, MN, and Billings, MT.

Today, the company has 1830 stores in 26 states. Total sales were $2.5 billion for the year ending 2007.

Executive officers of the company include David O'Reilly, Chairman of the Board; Greg Henslee, Chief Executive Officer and Co-President; Ted Wise, Chief Operating Officer and Co-President; Tom McFall, Chief Financial Officer.

The company continues to plan for growth and expansion, projecting the addition of 205 new locations in 2008.

Throughout this time, the underlying spirit and philosophy of O'Reilly Automotive, Inc. has been one of growth and progress, both for the company and for its team members. This remains the policy to which the company is dedicated today.