Before reaching the age of ten, George Gross, Jr began competitive swimming, holding Ontario and Canadian records in relays.

At age 15 he became Ontario's Overall Points Champion three times, setting records in the 200 backstroke, 400 individual medley and the 800 and 1500 freestyle.

While attending Yale University, George was introduced to water polo and became the first inductee in the Yale Water Polo Hall of Fame where he was undefeated as the starting goalie in league play.

At the end of 1974 he was added to Canada's National Water Polo Team, marking the start of a career spanning thirteen years including two Olympics (1976 and 1984), five Pan American Games (winning two bronze medals), three World Aquatic Championships and two World Student Games.

At the world Aquatic Games in 1986 George was honored by being made flag bearer for Canada at the opening ceremonies. In all, George represented Canada at 170 international matches.