J. Marvin Leonard ("Mr. Marvin"), businessman and civic leader, son of Obadiah and Emma Clementine Leonard, was born on February 10, 1895, near Linden, Texas. His parents were farmers and for a time operated a small general store in Linden. A younger brother, Obadiah Paul Leonard, was a longtime partner in Leonard Brothers. Poor vision in one eye kept Marvin out of the army during World War I, but he took advantage of wartime prosperity to move to Dallas, where he worked in a store that specialized in salvaged merchandise. In 1918 he moved west to Fort Worth and on December 14 opened a store in which Obadiah joined him the next year. The business prospered and rapidly expanded beyond its original offering of groceries and salvaged merchandise. Leonard used extensive advertising, eye-catching events, and a commitment to low profit margin and high volume to turn the firm into the largest retail establishment in Fort Worth. By the 1930s Leonard Brothers dominated retailing in the Fort Worth area. Leonard also invested in real estate, banking, and oil.
Golf, particularly building golf courses, occupied much of his time. In 1934 he purchased 157 acres on the southwest side of Fort Worth and began to build a golf course. The Colonial Golf Club officially opened on January 29, 1936. After redesigning the course, Leonard persuaded the United States Golf Association to hold the 1941 United States Open at Colonial. From this tournament grew the Colonial National Invitation, with which Leonard was long associated. In December 1942 he sold Colonial to its members. Leonard often combined golf and business. In the 1950s he built the Shady Oaks course in Fort Worth. Earlier he had sponsored Ben Hogan on the professional tour. For a time Leonard was Hogan's partner in the production and sale of golf equipment. He also developed the residential areas around the Colonial and Shady Oaks clubs.
Leonard married Mary Elinor Vaughan in 1931. They had four daughters. He was a major financial supporter of the Lena Pope Home and Texas Wesleyan University. He sold his interest in the store to O. P. Leonard in 1965. He was a member of the First United Methodist Church in Fort Worth. He died on August 26, 1970, in Fort Worth.