Hayden (nicknames: Haydos, Unit) is a powerful and aggressive left hand opening batsman, known for his ability to score quickly at both Test and one day levels. He is particularly proficient when hitting down the ground. Hayden currently holds the records for the highest scores made by an Australian batsman in both the Test (380) and One Day International (181 not out) arenas. He formed one of the most prolific opening partnerships in world Test cricket for Australia with Justin Langer, and is currently partnered with Phil Jaques as an opener in the Australian Test team and Adam Gilchrist at the top of the Australian One Day International team.

Hayden also played in the Australian side that won the 2003 One Day International Cricket World Cup. He was dropped from the ODI squad because of poor form after The Ashes in 2005, though he could not be kept away from the ODI squad for long. He returned to the Australian squad in the 2006-07 Australian season after Simon Katich fell out of favour and Shane Watson was injured. He dominated the Cricket World Cup in the West Indies as the tournament's best batsman in 2007, scoring three centuries before the completion of the Super 8s section of the tournament.