Duke was introduced as the bookie of Nat Bussichio, who came in and collected a few bets from Nat every now and again. However, Brandon Walsh later started using Duke as his own bookie, at first betting small amounts of money on sports events. As time went on, however, Brandon began showing signs of gambling addiction and it wasn't long before Brandon owed Duke more money than he could pay. After Duke showed up and threatened Brandon, Nat stepped in and paid Brandon's debt, telling Duke not to take another bet from him again.