Paddon was introduced into motorsport at an early age, his father Chris being a rally driver, beginning his career competing in karting. He competed in his first rally in 2002, at the age of 15. In 2005, he rolled and burnt his car in Rally Canterbury 2005. In 2006 he began competing in the New Zealand Rally Championship in a Mitsubishi Lancer Evolution VIII, winning both the Junior and Rookie titles. In 2007 he made his World Rally Championship debut competing in the Production World Rally Championship category at his home event in New Zealand as a wildcard entry, and then in the Team Jordan entry for Rally GB. In the New Zealand championship he retained his Junior title and came within a point of winning the championship outright. In 2008 he competed in a new Mitsubishi Evo IX, winning the New Zealand title. He also finished 13th overall and fourth in PWRC on his home round of the WRC.

In 2009 he retained his New Zealand title, won the Pacific Cup, and also qualified for the Pirelli Star Driver Asia-Pacific final at the 2009 Rally Australia. Paddon was the fastest of the drivers on the opening day’s stages, meaning he won the Pirelli Star Driver scholarship, giving him a fully funded programme for six events of the 2010 World Rally Championship season. Paddon’s event got even better when he finished ninth overall, ahead of all of the PWRC regulars. Paddon also won a $50,000 International Rising Stars Scholarship run by Rally of New Zealand, giving him the additional funding needed to complete a full 2010 PWRC campaign in addition to the PSD events.

In 2010, Paddon won the PWRC category of Rally New Zealand in his own Evo IX, finishing 14th overall. He then finished third and second in PWRC on Rally Finland and Rallye Deutschland in the Pirelli Star Driver Evo X.

In 2011, Paddon contested a full PWRC season, consisting of 6 Rounds; Portugal, Argentina, Finland, Australia, Spain and GB. He competed under his newly formed team New Zealand World Rally Team and in a surprising move, Paddon switched to a Subaru for the 2011 season, as he had usually run in a Mitsubishi. Paddon drove a STR11 Subaru Impreza N4 run by Belgian Team Symtech Racing. Paddon’s 2011 season proved to be a breakthrough as he took 1st place in four rallies consecutively: Portugal, Argentina, Finland and Australia, where he became 2011 P-WRC Champion.

The 2012 season saw Paddon move to the S-WRC championship in a Škoda Fabia S2000. After a 4th place among the S-WRC finishers in Sweden, he took his first S-WRC win in his second rally in the car at 2012 Rally de Portugal, which saw many competitors, including Paddon, have breakdowns.

2014 saw Paddon’s first stage win in the World Rally Championship during the Rally Catalunya in Spain.

In 2015, Paddon took his first ever lead of a WRC event in the Rally d’Italia. Paddon was the first New Zealander to lead a World Rally Championship event since Possum Bourne held the lead in the 1999 Rally New Zealand and the first one to do so outside of his country. He finished second overall, behind Sébastien Ogier, after a careful performance and many stage wins.

In 2016, on the 4th round, the YPF Rally Argentina, Paddon took his – and New Zealand’s – first WRC win by 13.3 seconds from Sébastien Ogier. His co-driver, John Kennard also became the oldest co-driver to win a WRC round at 57 years of age. Notably and perhaps controversially he celebrated the victory with a black and silver fern flag rather than the flag of New Zealand, following the failed flag referendum held earlier in the year. His intent was to distinguish the New Zealand flag from the Australian flag, where confusions still exists, even when, at the time of the victory, he was not competing against Australian drivers or co-drivers.