An accomplished swimmer and coach, Grant learned to swim at the San Antonio Country Club under Coach Jack Tolar, where he won his first “High Point” trophy at six years old. In the summer of 1953, at age fourteen, he began swimming competitively with the San Antonio Aquatic Club coached by Roy Kneip. That summer he and a group of boys started the Alamo Heights High School Swim Team. He ended his high school career as a three-time all-American and set national Junior Olympic records in the 200-meter freestyle and the 400-meter freestyle. Competing for SMU, he won all three 1650 titles at the Southwest Conference Championships during his varsity eligibility. In 1959, he won the High Point trophy and set a new Southwest Conference record of 18:34, which was the fastest time in the NCAA that year. After graduating from SMU, Grant became head coach of the San Antonio Aquatic Club for the 1960 summer season, winning the Texas TAAF State Championship and ending the Dad's Club's string of championships. In the fall of 1960, he enrolled in the MBA program at UT Austin where he was also Coach Hank Chapman's assistant and coach of the UT freshman team. After receiving his MBA, Grant entered the business world and has received many honors, including being inducted into the UT Austin School of Business Hall of Fame, Texas Business Hall of Fame, Texas Banking Hall of Fame, Dallas Business Hall of Fame, Horatio Alger Association of Distinguished Americans, and 2002 American Banker of the Year. Through the years he maintained his interest in swimming and in 1990 he moved to Dallas and began swimming with Dallas Aquatic Masters. In 1995, he placed third in the 400 IM and second in the 200 IM at the Masters Nationals. In 2017, he and his wife spearheaded a campaign with a $1.5 million donation to build a new natatorium at SMU.