He was primarily a right-handed middle-order batsman with a 'classical' technique, known in particular for his elegant strokemaking square of the wicket on the off-side and through the covers.

Martyn was also an occasional medium-pacer and distinguished fieldsman primarily in the covers who was capable of creating spectacular run-outs.

Martyn moved with his family to Perth, Western Australia at the age of three, and was educated at Girrawheen Senior High School, before being selected for the Australian Cricket Academy in Adelaide in 1990.

After returning to the domestic arena Martyn was appointed as captain of Western Australia in the 1994/95 season at the age of 23, the youngest player to have been given the honour.

[3] Noted for his daring and sometimes cavalier strokeplay, Martyn was selected to make his Test debut against the West Indies in November, 1992 at the Gabba, a surprise replacement for Dean Jones.

With Australia stumbling while chasing a small target of 117 against South Africa, Martyn had trouble scoring, with an unconvincing 6 from 59 balls in almost two hours as he and Craig McDermott took the total from 8–75 to within sight of victory at 8–110.

He played one test during that summer, replacing an injured Steve Waugh for Australia's victory at Adelaide where he remained not out in both innings.

His chance to consolidate a permanent position in the side came during the 2001 Ashes tour where he replaced fellow West Australian Justin Langer in the first test.

His best form came over a twelve-month period beginning in March 2004 where he scored two crucial centuries to help Australia to a 3–0 series whitewash in Sri Lanka.

[9] Following a poor Ashes tour of England in 2005, where he recorded a total of 178 runs at an average of 19.77, Martyn was dropped from the Australian Test side to play in the ICC Super Series 2005.

He was recalled to the Test squad at the expense of Brad Hodge for the three-Test series in South Africa in March and April 2006.

He also played an important unbeaten innings in the final against the West Indies to help Australia win the tournament for the first time.

Despite his poor form Martyn was widely expected to retain his place due to Shane Watson's lack of fitness and the fact that the third test was to be played at the W.A.C.A.

[30] His last ODI century was against India on 1 November 2003 at Wankhede Stadium, Mumbai where he scored 100 runs and also won the man of the match award.