As a fighter pilot, Sargeant's mission in the A-4M Skyhawk was to provide offensive air support, armed reconnaissance, and air-defense for Marine expeditionary forces, and he continued to serve in the Marine Corps Reserves as a pilot, graduating from Navy Fighter Weapons School (Top Gun), and attaining the rank of Major before becoming inactive after 11 years of continual active duty and reserve service.

In 1989 Sargeant introduced innovations into the international market, such as ISO bitumen containers, that would enable the shipment of his asphalt products to remote destinations worldwide.

Sargeant continued acquisition of large tankers throughout the remainder of the 1990s and into the next millennium, accumulating a dozen ships by the time of the Iraq War.

In a tip of the hat to his alma mater FSU, Sargeant would go on to name one large tanker, a 108.5 meter ship, the Asphalt Seminole.

[7][8][9][10] A Pentagon audit has found that the federal government overpaid Harry Sargeant III by as much as $204 million on several military contracts worth nearly $2.7 billion.

Rep. Henry A. Waxman (D-Calif.), who led the probe, asserted in a letter to Defense Secretary Robert M. Gates that Sargeant had won the three jet fuel contracts, despite having among the highest bids, because he had an effective monopoly over the routes.

He resigned the post shortly before a Sargeant Marine employee, sales coordinator Ala'a al-Ali, was indicted for illegal donations to the campaigns of Charlie Crist and John McCain.