Possessing a lanky frame and a composure belying his age, Ismail was called up by national team coach Radojko Avramovic into the Lions squad for the first time in September 2004 after a series of promising performances for the Under-18 and U-21 teams. But he only got his first team debut for the Singapore on 28 December 2006, in the invitational tournament, King's Cup held in Thailand, against Vietnam.
A mid-season transfer to Warriors F.C., Ismail played an exception role in marshalling the defense for the Warriors. Wearing the number 4 shirt, he made numerous tackles to deny the opponents from scoring. Ismail was instrumental in the Warriors 1-0 win over Albirex Niigata S FC when they clinched their first title in 5 years and their 9th title in the league's 19 years history.