[1] A right-arm fast bowler, he was also a competent lower-order batsman whose unbeaten 201 in his last Test match is the highest score by a night-watchman in international cricket.

He also played for South Australia, Yorkshire and Glamorgan at first-class level, and was an AIS Australian Cricket Academy scholarship holder in 1995.

[5] Jason Gillespie is a descendant on his father's side of the Kamilaroi people of Indigenous Australians, and is the first acknowledged Aboriginal male to become a Test cricketer.

[16] In the second Test against Bangladesh at Chittagong on 19 April 2006, Gillespie (201 not out) set the world record (on his 31st birthday) for the highest individual score by a nightwatchman.

Gillespie was awarded man-of-the-match honours for his double century in the first innings and he was also named man of the series for his efforts that included eight wickets, at an average of 11.3.

In Australia's 1999 tour of Sri Lanka, he was involved in a sickening outfield collision when both he and Steve Waugh were running to take a catch.

[23][24][25] Gillespie's career was cut short by a shoulder injury while fielding for South Australia, leading to his retirement.

[26] Gillespie was drafted in as the bowling coach of Indian Premier League team Kings XI Punjab after their opening match against Pune Warriors in April 2011.

In July 2017, Gillespie was appointed as the interim head coach for the Papua New Guinea national team replacing former New Zealand Test player, Dipak Patel.

[35] In October 2024, Gillespie was appointed coach of the white ball team on an interim basis following the departure of South Africa's Gary Kirsten.