Valk had a ten-year NHL career, debuting with the Vancouver Canucks in the 1990–91 season, scoring ten goals and eleven assists for twenty-one points, while recording sixty-seven penalty minutes.
Valk's strongest career year came in 1993–94, when he recorded forty-five points in seventy-eight games for the Mighty Ducks of Anaheim, after being selected in the NHL's expansion draft.
Valk became a player-coach that Pat Quinn depended on, fighting off opponents in crucial situations while also being an offensive threat.
Today, Garry coaches his son's junior hockey team in North Vancouver, British Columbia, and was featured in a Canadian Business Magazine article on athletes who have gone on to be successful after their careers.
He is also a Vancouver Canucks analyst on the sports news show Sportsnet Connected In 2010, developers of a downtown Toronto condominium project enlisted the public's assistance in picking a name for the structure.