Robertson is the grandson of Texas oil magnate Hugh Roy Cullen, the founder of Quintana Petroleum.
Robertson was an All-American linebacker at the University of Texas, captaining the team to a victory at the 1969 Cotton Bowl Classic.
[2] Robertson inherited Quintana's large holdings in oil but, in the 1980s, decided to invest his fortune in coal.
His greatest success came with the filly Bold 'n Determined who was inducted into the United States Racing Hall of Fame in 1997.
Among the best of Robertson's other runners was the homebred Turkoman, a son of Hall of Fame inductee Alydar.