[2] Cooper was in Australia's under-19 team for the 2006 Under-19 Cricket World Cup, and in the lead up to the tournament he made his Youth ODI debut against India.

[14] Cooper was selected to play for the Australian Institute of Sports in an Emerging Players Tournament over the 2009 winter, batting at number 3 and holding the team together with little support on multiple occasions.

[17][18][19] His breakout performance came near the end of the season when he played a tour match for the Prime Minister's XI against the West Indies cricket team.

[20] Cooper qualified to play for the Netherlands national cricket team as his mother was born in Dutch New Guinea.

[28] At the end of tournament he continued his string of good form with his maiden century and a score of 96 in two matches against Afghanistan.

[26] He played several more one-day matches for the Netherlands during the 2010 season, including against Bangladesh, a Zimbabwe XI[31] and Ireland.

[46] After the BBL he had another match-winning performance with 60 not out to lead South Australia to an unlikely one-wicket victory over Victoria despite an extraordinary Jon Holland spell of 6/29.

[52] Cooper was selected to play again for the Netherlands in the 2014 ICC World Twenty20, replacing Tim Gruijters due to a back injury.

The ICC said that the correct process of obtaining independent medical advice had been followed, so they allowed Cooper to play in the tournament.

[53] Cooper was the second-highest run-scorer of the entire tournament, playing seven matches and scoring 231 runs at an average of 57.75 and a strike-rate of 137.50.

[54] In the 2014 winter Cooper played for Australia A in a quadrangular series due to Phillip Hughes pulling out from the team.

[21] Cooper was at the non-strikers end on 25 November 2014 when Hughes, then both his teammate and his roommate, was struck by a cricket ball in his neck.

The Redbacks were patient and waited for him to improve,[63] but he was dropped from the team for the last three games of the Sheffield Shield season.

[67] Despite having lost his contract with South Australia, Cooper continued to play for them in both the One Day Cup and the Sheffield Shield.

He top-scored for the Redbacks in the Sheffield Shield with 736 runs at an average of 38.73, and midway through the season he'd played enough matches to get upgraded to a contract.