O'Connor became the second youngest Wallaby in Australian rugby history, behind only Queensland wing Brian Ford in 1957, when he made his Test debut against Italy in 2008. He made his first start in green and gold against the Barbarians at Wembley later that year.

Born in Australia, O'Connor grew up in New Zealand. A junior league player, in the league hotbed of Te Atatu, his first rugby experiences came watching the Blues at Eden Park before a move back to Australia gave him a start in union.

A hat-trick of tries against Italy in Australia's opening Test of 2009 increased his stock further and paved a way to further honours during the 2009 Tri-Nations. Following an injury to centre Stirling Mortlock, O'Connor got a run in the side for the first time, but endured a difficult return to Eden Park against the All Blacks. He was included in the Wallabies' end-of-year tour party but made only replacement appearances for the Test side.

During the year, there had been speculation linking him with a move away from Western Force, but he signed a new deal to remain with the Perth Super 14 franchise. His future sorted, O'Connor enjoyed a successful 2010, becoming a mainstay in the Australia starting XV. However, while he began the international season at fullback, he was moved out to the wing by head coach Robbie Deans for the Tri-Nations. The move worked out well for the elusive, fleet-of-foot O'Connor, who ended the campaign with four tries in his final three games.

He also crossed the line during a famous win for the Wallabies over New Zealand in Hong Kong later that year, scoring a try to level the scores before stepping up to seal the win with a brilliant conversion.

Following the 2011 Super Rugby season, O'Connor announced he would join the Melbourne Rebels for the 2012 campaign. O'Connor would later be joined at the Rebels by fellow Wallaby back Kurtley Beale.

O'Connor missed out on the Tri-Nations-clinching 25-20 victory over New Zealand through suspension after going AWOL and failing to attend the official World Cup squad announcement. However, he returned to the squad as a replacement for Australia's opening game against Italy and then regained his starting place against Ireland.

O'Connor went on to perform well for the Wallabies as they finished third overall in the World Cup. Following the tournament, he impressed at fly-half for Australia against the Barbarians in their end of season tour and looked set to retain the No.10 jersey for the opening Test of 2012 with Quade Cooper recovering from a knee injury, but a lacerated liver suffered on Super Rugby duty sidelined him for six weeks at a key stage of the season.