21 year old defensive midfielder, Ivar Ingimarsson, from Icelandic club IBV, had a steady game for Norwich City Reserves in their 6-0 victory over Luton on 19th November 1998. He was described as fulfilling his role with the minimum of fuss. Bruce Rioch decided not to retain Ivar or his fellow Scandinavian triallists Jesper Mattson and Rune Johansen. Ivar had played previously for Valur and IBV in Iceland

Ivar joined Third Division side Torquay on loan in October 1999 and scored on his debut in a 2-1 victory at league leaders Barnet on 23rd October 1999. However the Evening Standard reported on 2nd November 1999 that Ivar had signed for Brentford. This was later confirmed on 17th November and the fee said to be £150,000. Ivar had made 67 league appearances for Brentford by the end of 2000/01 and had won his first international cap.

Brentford just failed to win promotion from Division Two, losing in the play off final to Stoke. Ivar's form won him the attention of various clubs (or at least the section of the media responsible for speculation). The Sunday People claimed on May 19 2002 that both Ipswich and Watford were keen to swoop whilst Teamtalk added Sheffield Wednesday to the list of contenders the following day. Ivar was released on a free transfer in June 2002 as Brentford could no longer afford to pay his wages. Despite media rumours in June 2002 linking him with Norwich, their suggestion that he could also join Wolves came true on 1st July 2002.

Unable to establish himself at Wolves, he joined Brighton on a month's loan on February 10th 2003 working once again with Steve Coppell (his manager at Brentford). Returning to Wolbes at the end of the season, Northampton made an offer to bring Ivar to the Sixfields Stadium. To the Cobblers' disgust, Wolves asked for £250000 when they had quopted £50000 during the previous season. At the end of August 2003, Ivar was linked with a move to QPR to replace former England Under-21 defender Clarke Carlisle who had fallen out with Rangers' management.

Despite a rival bid from Crystal Palace, Ivar teamed with his former Brentford and Brighton manager Steve Coppell on 23rd October 2003 when Coppell made him his first signing for his new club Reading (Coppell replaced Alan Pardew). Ivar cost £100k with another £75k based on appearances and a sell-on clause of 25%. His chances were limited at Wolves and they sought to cash in on him rather than lose him when his contract expired at the end of the season.

Towards the end of the 2004/5 season, Ivar was linked with moves to Wigan and/or West Ham. Rejecting them, he played a key role in Reading's 2005/6 season which saw them promoted to the Premiership for the first time in their history following a 1-1 draw at Leicester on 25th March 2006.

Ivar was released by Reading on 2nd June 2011, shortly following their Championship play-off final defeat to Swansea three days previously. He had made 282 appearances for Reading but injuries took their toll. He signed a one year contract with Ipswich on 13th June 2011.

His contract with Ipswich was terminated by mutual consent on 9th January 2012. He had played eight games for Ipswich.