After hanging up his boots at the age of 22, King took up several odd jobs such as working as a bar man before deciding to give rugby league another go in 2003, signing with the Cronulla-Sutherland Sharks. King couldn't make it out of the reserve grade at the Cronulla. He began to look for other clubs, eventually settling on moving to the Brisbane Norths club in Queensland, one of the feeder clubs for the Melbourne Storm.
2005 became the season where King would stamp his mark on rugby league, beginning the season by scoring seven tries in the first seven games of the season including a set of doubles against Brisbane and Canberra and yet again impressing City vs Country selectors enough to be again selected in the annual clash. After further impressive performances King was called up for his first major representative honour, being selected for the New South Wales State of Origin side for all three games in 2005. King finished the 2005 season at Melbourne with fourteen tries, and coupled with his three for New South Wales, earned a spot in the Australian international side for the 2005 tour of Great Britain.
The following year in 2006 started off slowly for King, but as the year progressed he worked his way into form again. He was once again selected in the New South Wales side again for the annual State of Origin clash, which NSW lost the series 2-1 to Queensland. After his side's 15-8 loss to the Brisbane Broncos in the 2006 NRL grand final, in which he starred by scoring a try, he cost his club $5000 after publicly criticising match referee Paul Simpkins.
After being consistently linked with a move to the European Super League during the early half of 2007, Matt King finally announced on 10 July, 2007, that he had signed a four year deal with the Warrington Wolves. The deal is worth approximately AUD$600,000 a year, making King one of the highest paid players in rugby league.
In September 2007, he finally realised his dream of playing in a premiership. The Storm won convincingly over Manly-Warringah, 34-8, and King scored an inspiring try in his last game in the NRL. Overcome with emotions, King admitted when interviewed that he had been crying shortly after the victory and that this was "the best feeling ever".
After some impressive games for his club side at Melbourne along with two good displays for the Country team in both 2004 and 2005, King was selected for the New South Wales team in game one of the 2005 State of Origin series out of position on the wing as to his usual role at centre. King eventually played in all three matches, failing to score in the first two, yet crossed the line three times in the final match for a hat-trick in the series decider. Following the game he was awarded the first Brad Fittler Medal for New South Wales Player of the Series.
After some impressive performances during the 2005 season for both club and state, King was selected for the tour of Great Britain with the Australian international side. He played in every game on tour and was again selected out of position on the wing, yet played well enough to earn praise from the Great Britain and Ireland international winger Brian Carney who stated King was "the best winger in the world".
2006 and 2007 saw King yet again selected in the original squad for New South Wales, scoring two tries in the 2006 series and one try in the 2007 series.
| Team | Matches | Years |
|---|---|---|
| Melbourne Storm | 68 | 2003 - 2007 |
| Country | 2 | 2004 - 2005 |
| New South Wales | 9 | 2005 - 2007 |
| Australia | 18 | 2005 - 2006 |
"For a winger to have the impact he did in a game was incredible, his input to the team's performance was significant, especially in the second game. He had such an important bearing on the result. I knew he was a good player but I didn't know he was that good." (New South Wales coach Ricky Stuart, commenting on King's performances after the 2005 State of Origin.)
"I haven't had the rise of a normal first-grader so I really appreciate where I am at the moment and it's something I don't take for granted." (King comments on his unusual rise to fame and quick success.)