As a right-arm fast bowler, he played first class cricket for five counties Yorkshire, Lancashire, Nottinghamshire, Sussex and Leicestershire between 2004 and 2017.
"[5] In April 2012 Yorkshire's new head coach, Jason Gillespie, praised Shahzad's efforts, saying "Ajmal has got himself in as good a condition as he's ever been in his first-class career.
[8] On 10 October 2012, having been told he was free to leave Yorkshire, Shahzad signed a three-year contract to join Nottinghamshire.
[15] Shahzad was included in the performance squad who were training in Australia for the 2011 Ashes and ready to provide cover in the event of injuries.
[18][19] Shahzad was included in England's 15-man squad for the 2011 ICC World Cup held in Bangladesh, India, and Sri Lanka in March 2011.
[23] On his return to Yorkshire, he struggled for form so was left out of the England Test and ODI squads to face Sri Lanka in 2011.
He was selected in the England Performance Programme held over the 2011-12 English off-season,[24] but never played international cricket again.
Following his playing career, Shahzad initially became an assistant coach at Marylebone Cricket Club's youth team.