He won his first cap as a full Scottish international coming on as a substitute against Norway in a 2010 FIFA World Cup qualifier in 2008, notable for his missing an open goal from only yards out as the match finished 0–0 an event which Iwelumo has said "tortured" him.

Aarhus released him two years later in February 2000 and he had trials at Preston North End and Celtic – the team he supports – before signing a four-year deal with Stoke City.

He played four times for Cheltenham Town, scoring once against Mansfield[8] before being recalled back from his loan by Stoke City where he managed to build on his appearances without actually gaining a regular place in the first team, his most notable contribution possibly being the equaliser in the Potteries derby on 21 October 2001.

Bundesliga side Alemannia Aachen signed Iwelumo on a free transfer in July 2004, after rejecting the offer of a two-year contract from Brighton.

[18] It was confirmed that Iwelumo could leave Charlton as part of cost-cutting measures and he eventually signed for fellow Championship side Wolverhampton Wanderers in July 2008 on a two-year deal.

[19] Iwelumo scored a hat-trick for Wolves against Preston North End in a 3–1 win, taking his goal tally to eight for the season, where he was also sent off for an apparent head-butt on defender Sean St Ledger.

His season was ended prematurely after a high tackle from Lee Carsley in the game against promotion rivals Birmingham City left him with medial ligament damage.

[24] He regained fitness over the summer break but suffered more injury woe as he broke his metatarsal in Wolves' opening pre-season game against Australian club Perth Glory.

[25] He eventually returned to first team contention and made his Premier League debut in a 1–1 draw against Aston Villa in October 2009, though again suffered an injury setback which put him on the sidelines for a further month.

[26] When fit, his Premier League appearance were limited to fleeting substitute roles and he instead moved on a month's loan to Championship side Bristol City in February 2010 to gain more playing time.

[32] Following an injury to John Eustace at the start of the 2012–13 season and the departure of Martin Taylor, Iwelumo captained Watford for the first time against Derby County on 1 September 2012.

[39] Iwelumo was called up for the Scotland squad to tour South Korea in 2002 but had to withdraw as his club Stoke City were involved in the Football League Championship play-offs.

[43][44] For days after, Iwelumo constantly watched video replays of the incident but was determined not to be remembered for the miss, stated "I'm a proud Scot, I love my country and it's my dream to do well for them.

[49] In November 2016 he re-joined former club Chester as assistant manager to Jon McCarthy but continued to work as a pundit for Channel 5's Football League Show.