Tierney first played hurling to a high standard as a student at St. Brigid's Vocational School in
Loughrea. He was part of the school's senior team that won back-to-back
All-Ireland Vocational Schools SHC titles in 2000 and 2001. At club level, Tierney progressed to adult level with
Kilnadeema–Leitrim. He
captained the team to an
All-Ireland Club IHC final defeat by
Rower-Inistioge in 2014. Tierney's inter-county career with
Galway began at
minor level. He lined out at midfield when Galway were beaten by
Cork in the
2001 All-Ireland minor final. Tierney later progressed to
under-21 level and was at centre-forward on the team beaten by
Kilkenny in the
2003 All-Ireland under-21 final. He was a non-playing substitute when the
senior team was beaten by Cork in the
2005 All-Ireland final, however, he was released from the panel the following year. ==Personal life==