He spent six years at Ipswich, making over three hundred appearances and captaining the club to promotion to the Premier League through the First Division play-offs in 2000.

Initially rejected by Arsenal for being 'too small', Holland went to West Ham United where he moved up the ranks of the academy but did not play for the first team.

[3] In order to gain first team football, Holland joined South Coast side AFC Bournemouth in January 1995.

In total Holland made 59 appearances in all competitions during his first season at the club, scoring 12 goals, including a brace in a 3–0 away win over Torquay United in a League Cup second round tie.

He scored 10 goals in the league as Ipswich once again finished 3rd in the First Division, narrowly missing out on an automatic promotion place on the final day of the season.

Ipswich won the second leg 5–3 at Portman Road, in a match that also saw two Bolton Wanderers players red carded, with goals from Jamie Clapham, Martijn Reuser and a Jim Magilton Hat-trick.

[11] He continued to play regularly, scoring his first goals of the season on 18 August, netting a brace in a 6–1 win over Leicester City at Portman Road.

[13] His spell at Ipswich is remembered for the consistency he showed, after playing 223 consecutive games and only missing one league match (due to international duty) in the six years he was at Portman Road.

Combined with the end of his time at Bournemouth, Holland's sequence of 286 matches is among the highest in English league football.

[14] After Ipswich failed to win promotion in 2003, Holland moved back to the Premier League by joining Charlton Athletic on a four-year contract for an initial £750,000 fee,[15] which later rose to £900,000.

[19] His final match came in a 2–2 draw with Cardiff City on 21 April 2009,[20] and the club released him after relegation to League One at the end of the season.

[21] Although born in England, Holland qualified to play for the Republic of Ireland through his grandmother who hailed from County Monaghan.

[22] He made his international debut on 9 October 1999 in an away Euro 2000 qualifier against Macedonia, playing the last five minutes as a substitute for Mark Kennedy.

[24] Holland's first goal for the national team came on his fifth cap, the equaliser in a 1–1 draw with Portugal on 7 October 2000 in qualification for the 2002 FIFA World Cup.

[28] Following Ireland's failure to qualify for the 2006 World Cup, he announced his retirement from international football on 5 February 2006 having made 49 appearances and scoring five goals.

[29] He was one of several players and managers (including Danny Mills and Paul Jewell) who acted as summarisers for BBC Radio Five Live during the 2006 World Cup.

Holland has also appeared on the BBC television program A Question of Sport and the radio quiz Fighting Talk.

[31] Holland began work with RTÉ when he commentated alongside George Hamilton during the Rep. of Ireland and Brazil friendly.