With his birth country of New Zealand, Moss made 29 appearances, and was a member of their 2010 FIFA World Cup squad, although was controversially suspended for the first two games after an appeal for an earlier four-game ban was not submitted in time.

Moss made his senior debut with Sydney Olympic of the NSL, appearing in three games of the competition's final season.

Having e-mailed the eight inaugural clubs of the A-League, Moss received interest from New Zealand Knights, who signed him to a one-year contract having watched him play for Sydney Olympic.

Impressing over the summer with the national team, Moss signed on a free transfer with Dinamo București of Romania.

[3] Moss made his debut for Dinamo in first round of qualification for the UEFA Cup, starting both legs against Maltese club Hibernians in July.

Moss started the league opener against Național București on 30 July, but was replaced by Florin Matache for the club's next games.

Having hovered between second and third-choice in the first half of the season, Moss sought out of Romania during the winter break, calling the move abroad a "disaster".

In August 2007, Moss signed a two-year contract with A-League newcomers, the Wellington Phoenix, recruited by manager Ricki Herbert as part of a contingent of All Whites players.

However, injuries and dips in form during 2008–09 saw him share the starting jersey with fellow All Whites goalkeeper Paston, making just 13 appearances and keeping 3 clean sheets.

[11] Moss made 22 starts in the 2016–17 A-League for Wellington, notching five clean sheets, while missing a handful of games while on international duty.

[13] Moss had a nine-game run in the side, finishing with a pair of clean sheets, before Duncan returned to the starting lineup on 20 January.

He also started Newcastle's two games in the 2019 AFC Champions League qualification, as they fell short of reaching the group stage when they lost to Kashima Antlers.

Moss tore his calf attempting a goal kick against Sydney FC on 10 January 2020 and had to leave the game, being replaced by Lewis Italiano.

In what was the last game in the A-League before it was postponed due to the COVID-19 pandemic in Australia, Moss was given a five-minute run-out off the bench by new Jets manager Carl Robinson, seeing out a 2–1 victory over Melbourne City on 23 March.

Moss gained his first international recognition when called up for the New Zealand squad for a friendly match against Iran in October 2003, however he did not earn his first cap until a 1–0 win over Malaysia in February the following year.

[21] Moss was in goal for New Zealand's tour of Europe during the summer of 2006, as the All Whites picked up their first win over a European opponent when they beat Georgia 3–1.

In the third round of World Cup qualification, Moss started the two games against Tahiti, as New Zealand finished top of the group, setting up an intercontinental play-off with Mexico.

Three friendly matches in 2014, including a goalless draw with South Africa in which Moss captained the side,[25] proved to be his final caps for the national team, although he continued to be a part of the squad until 2017.