Nicknamed "Pup",[2] Clarke was a right-handed middle-order batsman, an occasional left-arm orthodox spin bowler and also a slip catcher.

[6] Clarke made his first-class debut for New South Wales as a seventeen-year-old in a game against the touring Indian side at the Sydney Cricket Ground in December 1999.

Despite not being considered a strong bowler, he bowled in fourth Test match at Wankhede Stadium in Mumbai and took six wickets for nine runs.

[11][15] After his early success in the team, Clarke began to struggle and didn't score another century in the following six Test series he played.

England responded with defensive bowling tactics to slow him down, and Clarke tried to improvise with aggressive shots and was dismissed.

[12][18][19] Clarke then helped Australia retain the 2007 Cricket World Cup in the West Indies where they did not lose a game.

He also made an unbeaten 60 against South Africa in the semi-final to guide Australia into the final at Barbados, against Sri Lanka.

He opened the batting in the final two games after a hip injury ruled out Matthew Hayden and he made two golden ducks.

In the tour-ending Twenty20 match Clarke dropped back down the order with the return of Hayden, and scored 25 not out in a heavy defeat.

Australian captain Ricky Ponting had declared that morning, setting India a total of 333 to chase and allowing Australia arguably too little time to bowl out the visitors.

Clarke's wickets ensured that Australia retained the Border–Gavaskar Trophy in 2008 and kept their world record equalling 16 match win streak alive.

[citation needed] Soon after Clarke joined up with the squad, he scored a century in the second Test in Antigua, going on to captain the side in the final two One Day Internationals, both of which were won, in the absence through injury of Ponting.

[citation needed] Clarke won the 2009 Allan Border Medal in a tie with Ricky Ponting both scoring 41 points, and was named Test Cricketer of the Year.

[30] Clarke was named as captain of Australia's Twenty20 side in October 2009,[34][35] taking over from Ricky Ponting, who retired from Twenty20 International cricket to prolong his career.

[36][37] In January 2011, Clarke was named as stand-in captain for the fifth Test of the 2010–11 Ashes Series at the SCG, replacing the injured Ricky Ponting.

[39] When Ponting stood down from the captaincy of the Australian Test and ODI sides after the 2011 World Cup, Clarke was appointed as his permanent replacement in both roles.

[40] His knock of 151 against South Africa at Cape Town was nominated to be one of the best Test batting performance of the year 2011 by ESPNcricinfo.

He joined with Ricky Ponting (134) in a partnership of 288, then added 334 with Michael Hussey (150*) before declaring on 329*, having started his innings with the score at 37/3.

[47] Following the Frank Worrell Trophy 2012, Ian Chappell said Clarke "is quickly establishing a well-deserved reputation for brave and aggressive captaincy.

[49] Three weeks before the 2013 Ashes series, Clarke requested to stand down from his role as a selector,[50] which also coincided with the sacking of coach Mickey Arthur and the naming of Darren Lehmann as his successor.

Mitchell Johnson described the team atmosphere as 'toxic' under his captaincy,[61][62] while Michael Hussey described the dressing room was stressful and tense.

[63][64] Several former players including John Buchanan[65][66][67] Andrew Symonds,[68][69] Matthew Hayden,[70][71] and Simon Katich[72][73][74] spoke against his captaincy.

Katich, a former team mainstay, blamed Clarke for effectively ending his career once he became captain in revenge for a post-match incident several years earlier which saw Katich grab Clarke by the throat following a row about the singing of Australia's team song in the dressing room.

[87] Clarke won the Allan Border Medal, considered to be the most prestigious individual prize in Australian cricket, four times, in 2005, 2009 (jointly with Ricky Ponting), 2012 and 2013.

[95][96] In June 2020, Clarke was made an Officer of the Order of Australia in the Queen's Birthday Honours, "for distinguished service to cricket as a player at the national and international level, through leadership roles, and to the community.

[113] The pair never married, and they ended their relationship in March 2010, with Clarke leaving the Australian cricket team's ongoing tour of New Zealand to call off their engagement.

[120] He was very close to former Australian Test opener Phillip Hughes, and was distraught at the 25-year-old's unexpected death after being hit in the neck by a short-pitched delivery during a Sheffield Shield match at the SCG in November 2014.