Davison began racing with success in Australian junior categories, winning the Victorian Formula Ford title in 2000 and the 2001 Australian Formula Ford Championship, competing in the same fields as future IndyCar driver Will Power. Seeking a path toward Formula One, he moved to Britain and contested the 2002 British Formula Renault Championship, finishing fourth. He then campaigned in British Formula 3 in 2003 and 2004 with Alan Docking Racing and Menu F3, though financial pressures curtailed his open-wheel ambitions.
In 2004, Davison tested a Minardi Formula One car at Misano alongside Will Power, organised by Australian team owner Paul Stoddart. Between his Formula 3 campaigns and securing a Supercars seat, he drove for A1 Team Australia in the inaugural A1 Grand Prix season, collecting a pair of sixth-place finishes in Portugal and Australia.
Davison made his Supercars debut in 2004 at Winton with Team Dynamik before joining Dick Johnson Racing in 2005 as a co-driver and then a full-time pilot from 2006. His years with Dick Johnson Racing produced steady improvement, culminating in a strong fifth in the 2008 championship and a maiden race win at Eastern Creek Raceway that year — the team's first round victory in seven years.
In 2009, Davison moved to the Holden Racing Team alongside Garth Tander and enjoyed the best season of his career. He finished second in the championship, scored a round win at Sandown, a race win at Queensland Raceway, and clinched victory in both the Phillip Island 500 and the Bathurst 1000 co-driving with Tander. The Bathurst win was his first at Mount Panorama, and he received the Barry Sheene Medal as the championship's best and fairest driver.
After a difficult 2010 plagued by technical problems, Davison joined Ford Performance Racing for 2011. He quickly re-established himself as a frontrunner, earning four pole positions and six podiums during the season. In 2012 he won the Clipsal 500 Adelaide and led the championship with six wins from eleven starts, but the endurance season brought bad luck and he finished fourth overall despite a maiden Bathurst 1000 pole position. In 2013 he finished third in the standings, just behind the Triple Eight Racing duo of Craig Lowndes and Jamie Whincup.
Davison joined Erebus Motorsport on a four-year contract in 2014, driving a Mercedes-Benz E63 AMG. The results were modest — fourteenth in 2014 and fifteenth in 2015 — with financial pressures eventually leading the team to release him early. His one highlight was a race win at the 2015 Perth Super Sprint.
He moved to Tekno Autosports in 2016, returning to Holden machinery. The partnership yielded immediate success: a round win in Tasmania and then, at the Bathurst 1000, a dramatic second Bathurst crown. Davison capitalised on late-race chaos among the leaders to take the chequered flag despite never having led a lap.
From 2018 through to the team's demise in 2020, Davison competed with 23Red Racing, before returning to Dick Johnson Racing for the 2021 Supercars Championship season, partnering Anton de Pasquale.
Outside Supercars, Davison has competed regularly in the Bathurst 12 Hour, recording a best outright result of third in 2014 in an Erebus Motorsport Mercedes-Benz SLS AMG.
His family's motorsport pedigree is extraordinary. His grandfather Lex Davison won the Australian Grand Prix four times and the 1957 Australian Drivers' Championship. His brother Alex Davison won the 2004 Australian Carrera Cup Championship and competed in Supercars for several years. Cousin James Davison has raced in the IndyCar Series, while his grandmother Diana Davison was one of the first female racing drivers in Australia. His stepgrandfather Tony Gaze was a decorated World War II fighter pilot who also competed in Formula One.