During his rugby playing career Wallace played with
UCC,
Munster,
Blackrock College RFC, Leinster before moving to professional club,
Saracens whom he played with from 1996 to 2001 before returning to
Leinster in 2001. He played at international level with Ireland and the
British Lions, representing Ireland at junior levels before making his full international debut against
Japan in the
1995 Rugby World Cup in
Bloemfontein to play alongside his brother Richard. He went on to win 46 caps for Ireland between 1995 and 2002. His final match for Ireland was against
Georgia in a world cup qualifier at
Lansdowne Road in September 2002. Wallace was selected to tour South Africa with the
1997 British Lions. He became one of only five members of the tour who played the full duration of all three tests. He was a very influential player in the winning of the series, facing
Os du Randt in the
scrum and was subsequently described by captain,
Martin Johnson, as his "player of the series", ==Post rugby career==