Garry Jack , nicknamed “Jimmy Jack” is an Australian former rugby league footballer and coach who was a highly prominent player of his era. He was a distinguished member of the Australian Kangaroos national team and a star player for the Balmain Tigers. Jack was a fullback for the Tigers during the late 1980s, and early 1990s, under the captaincy of Wayne Pearce and the coaching of Warren Ryan. Jack also represented the New South Wales State of Origin team on 17 occasions. Aggressive, fast and safe under pressure, Jack was seen at his best running the ball back strongly and breaking the first line of defence.

GARRY Jack commenced his first grade career with Western Suburbs Magpies in 1981. The dashing, snowy-haired fullback trialled with Wests on the recommendation of his Wests Wollongong coach Paul Sait in 1981 and, after playing the latter part of the season in first grade, he was signed by Balmain secretary Keith Barnes. The following year he moved to Balmain Tigers where he played for the rest of his Australian first grade career. His association with English rugby league began at the end of the 1986 Kangaroo tour when he stayed on to play for Salford before returning to the Tigers. The 'Golden Boot' awarded to Gary Jack as the finest league player in the world in 1987 is a good measure of the standing he attained during his career.

He was member of the consecutive Balmain teams which fell at the final hurdle to firstly Canterbury-Bankstown in the 1988 Grand Final and then to Canberra in 1989. After the disappointment of two grand final losses with the Tigers, Jack tried to regain his place in the rep teams but found the door firmly closed.

1991 saw the departure of Warren Ryan as Balmain coach and the arrival of former Wallaby coach, Alan Jones. The years playing under Jones at Balmain were unhappy ones for Jack and eventually after he had left the club in 1992, he launched an attack on Jones' ability as a coach following his 'surprise' reappointment for a third year. When his Australian club career ended having surpassed Keith Barnes' club record for first grade matches, he returned to England to play his final season with the Sheffield Eagles. Jack was appointed coach of English club Salford in July 1993, but departed following their relegation from the top flight at the end of the 1994–95 Rugby Football League season.

He returned to the Tigers that year to play the final season of his career but was back in the news in 1999 when he sued former Manly forward Ian Roberts for injuries suffered after an altercation in a match in 1991.

Jack's sons Kieren and Brandon both played for the Sydney Swans in the Australian Football League. Another son, Rhys Jack, played in the Bulldogs Toyota Cup (Under-20s) team and Balmain in the New South Wales Cup. On 22 January 2021, Harry Jack suffered a cardiac arrest. A friend was able to apply CPR until an ambulance arrived.