Blaney began his playing career with native province Leinster in 1994, before joining their rivals Munster ahead of the 2000–01 season and spending five seasons with the southern province, during which time they reached the Heineken Cup final in 2002, won the Celtic League in 2002–03 and the Celtic Cup in 2004–05. Blaney also represented Ireland A during his career, the team one level below the senior national team.