Miller first played for Leinster during the 1995–96 season while still attached to Old Wesley. After his spell with Leicester Tigers he returned to Ireland and initially linked up with Terenure College RFC and Ulster.[5] In 2000, he returned to Leinster and went on to make 148 appearances for the province in the Celtic League and the Heineken Cup. Back at Leinster he helped them win the 2001–02 Celtic League title.[4]
Rugby international
Ireland
As well as winning senior caps, Miller also represented Ireland at schoolboy, U21 and A levels. In 1996, he was a prominent member of the Ireland U21 team that won a Triple Crown for the first time. Between 1997 and 2005, Miller made 48 appearances and scored 30 points, including 6 tries, for Ireland. He made his international debut in a friendly against Italy on 4 January 1997. He went on to play for Ireland at both the 1999 and 2003 World Cups. He scored two of six his tries in one game against Namibia during the 2003 Rugby World Cup. He made his final appearance for Ireland in a friendly against Japan on 19 June 2005.[6][7]
Miller has also played for the Barbarians several times. In May 2004 he was included in their squad for games against England, Wales and Scotland.[9] On 25 May 2005 he featured in a 38–7 defeat against Scotland at Pittodrie.[10]
Since finishing with Gaelic football, Miller set up his own personal training company called the real golf solution.[13]
Coaching
Miller has also had a successful coaching career. In September 2006 he undertook a coaching position in Wesley College, Dublin until 2009. He also coached for Old Wesley as well as Saint Gerard's School.
In 2011, he was appointed Head Coach Blackrock College Rugby Club Dublin. From 2009 to 2012, Miller also served as Head and assistant coach to the Leinster U18 Club (youths) team and helped the team win three interprovincial championships in a row during his tenure.
In August 2012 Miller was appointed Head Coach of CYM Rugby Club in Terenure Dublin, following in the footsteps of club luminaries like Ray Fagan. In May 2013 Miller was appointed Head Coach of Seapoint Rugby Club, a Division 2A side in South Dublin playing in the All-Ireland League.
Beginning in 2016, Miller coached the men's senior firsts team in the Wicklow-based Arklow Rugby Club, and the all boys private school Catholic University School on Lower Leeson Street in Dublin, until 2019 .