O. P. Leonard, retailer and investor, son of Obadiah John Thomas and Emma Clementine (Hill) Leonard, was born on September 4, 1898, near Linden in Cass County, Texas. His parents farmed and briefly operated a general store in Linden. He attended school there and after graduating from high school attended Texas A&M. He moved to Dallas and then Fort Worth, where in 1918 he worked for his older brother Marvin's grocery store, across from the Tarrant County Courthouse.
Leonard, known as "Mr. Obie," was in charge of store operations at Leonard Brothers. In this role he participated in the design, construction, and renovation of a store that eventually sprawled over nine acres of downtown Fort Worth. After World War II he and his crew built and installed the first escalator in Texas. In the early 1960s he supervised the construction of a subway from off-site parking to the basement of Leonard Brothers. When the M&O (Marvin and Obadiah) Subway opened in February 1963, it was the only privately owned subway in the United States. In the early 1930s Leonard began buying land in Hood and Wharton Counties. In 1933 he planted 400 acres of pecan trees. From then until his death he constantly purchased more land and planted more trees. By 1974 he was harvesting about 4½ million pounds of pecans a year and was the largest pecan grower in Texas. In the 1940s and 1950s Leonard operated a company that pioneered in the manufacture of automobile air-conditioners and sold units to Ford, Chrysler, and General Motors. In 1954 he sold the company and characteristically was paid down to the penny for the units in stock. Leonard was the founder and president of the David Crockett Life Insurance Company. He helped start water-utility companies in Johnson and Hood counties. He was head of the Trinity River Authority and director of the Trinity Improvement Association.
Leonard married Margery Fay Wooldridge in 1925; they had two daughters and two sons. The couple generously supported the Boy Scouts. O. P. Leonard purchased his brother's interest in the store in 1965. In 1967 he sold Leonard Brothers to Charles David Tandy. He died on December 25, 1987.