Born in Shreveport, La., Blanton was raised in Houston. After graduating from Lamar High School, he earned a B.A. at the University of Texas at Austin in 1947 and a law degree from UT Law School in 1950. He went to work for Eddy C. Scurlock at Scurlock Oil Company and rose through the ranks to become president in 1958. In 1983, a year after the company was sold to Ashland Oil, he became CEO and chairman. In 1988, he retired from Ashland and became president of Eddy Refining Company. A longtime Houston civic leader, Blanton served as chairman of the board of Houston Endowment and was on numerous boards, including the Methodist Hospital Healthcare System, the Texas Medical Center, the Houston Zoo and the Jesse Jones School of Management at Rice University. During his tenure at Houston Endowment, the philanthropy's assets jumped from $400 million to $1 billion. He also served as a regent of the University of Texas from 1985-1991 and served as chairman of the UT board from 1987–1989. During his tenure as chairman, he worked closely with the Texas legislature, which passed a tax increase to raise funds for higher education in the state to make up for a 26 percent shortfall. In 1997, the University of Texas at Austin renamed its art museum the Blanton Museum of Art in his honor after receiving a $12 million donation from Houston Endowment Inc. Blanton was also instrumental in raising funds for the Lady Bird Johnson Wildflower Center in Austin. Blanton was married to Laura Lee Scurlock, the daughter of Eddy C. Scurlock, until her death in 1999. (The Laura Lee Blanton Building at Southern Methodist University is named for her.) They are survived by three children, Elizabeth Blanton Wareing, Jack S. Blanton Jr. and Eddy S. Blanton. He was later married to the late Lucinda Bailey Blanton, and is survived by his current wife, Ginger Nelson Blanton, whom he married in 2002.