After trialing with both
St George and
Souths, Simmons was eventually given a contract in 1980 with Penrith. Simmons played much of his first year at lock but was moved to hooker late in the 1981 season. Simmons was first selected to represent
New South Wales as a hooker for games II and III of the
1984 State of Origin series, replacing
Rex Wright who had been chosen for game I. After missing the
1985 series when selectors chose
Balmain's
Benny Elias instead, Simmons regained his place for the Blues in the successful
1986 series against
Queensland, including a Man of the Match in game I. Simmons secured a place as the first Penrith player to represent Australia when made his Test debut in the first match against
New Zealand at
Carlaw Park in
Auckland, and played in ten international games over the next year. Simmons' final Test appearance came in Australia at
Lang Park,
Brisbane, against New Zealand, losing 6–13. At the end of the
1986 NSWRL season, Simmons was selected for the undefeated
1986 Kangaroo tour and played in all six tests on the tour against
Papua New Guinea,
Great Britain and
France. Simmons and
Greg Alexander became the first Penrith players to be selected for a
Kangaroo Tour. Simmons was selected for all games of the
1987 State of Origin series, including the fourth game held at the
Veterans Memorial Stadium in
Long Beach,
California (United States). His last appearance in a New South Wales jersey was in game I of the
1988 series at the
Sydney Football Stadium, with NSW losing 18–26. The Blues would not win another game until Game 1 of the
1990 series. In 1983, Simmons was appointed captain of the team, a position he retained until 1990 when he captained the Panthers in the
1990 Grand Final loss to the
Canberra Raiders. Despite struggling with injuries, he memorably scored two tries in the
1991 Grand Final against the same opponents. The Panthers won their first premiership, and Simmons retired with his second try late in the game (and Alexander's brilliant sideline conversion) sealing the win for the
Phil Gould coached Panthers. In the post-game celebrations, Simmons said he wanted to have a beer with every Penrith supporter. He also stated that despite being overjoyed at finally winning a premiership, nothing could erase the bad memory of losing the 1990 decider to the Raiders. Following the grand final victory he travelled with the Panthers to England for the
1991 World Club Challenge which was lost to Wigan. In October 2004, Simmons was named at hooker in the Panthers' "Team of Legends'". ==Coaching career==