George Duffin was born at the inner Sydney suburb of Stanmore. He grew up at Ashfield where he first played rugby union. George made his way through the Ashfield Borough and Second Grade teams until he switched across to play rugby league with Wests in 1908.
He played fullback in four First Grade games for Wests in 1908 including the very first game against Balmain. That year George was selected to play for Metropolis against the New Zealand Maoris.