[1] Guðjón has three sons who have also played professional football, namely: Bjarni, Joey and Þórður Guðjónsson.

Guðjón came back to Akranes after his spell at KR and guided the team to win the Icelandic league and the Cup in 1996.

The game that took place at Stade de France was one that put Icelandic football to a higher standard.

Guðjón brought in a number of his fellow countrymen to the club with the arrival of Einar Daníelsson, Sigursteinn Gíslason, Brynjar Gunnarsson and his son Bjarni Guðjónsson.

Good results continued as more Scandinavian players arrived at the club such as Frode Kippe, Mikael Hansson and Arnar Gunnlaugsson.

[5] Stoke also reached the 2000 Football League Trophy Final where they faced Bristol City in front of 75,057 at Wembley.

[5] In 2000–01 Guðjón was again busy bringing in Icelandic players with Ríkharður Daðason, Stefán Þórðarson, Birkir Kristinsson and Danish defender Henrik Risom all agreeing to move to Stoke-on-Trent.

He sold both Graham Kavanagh and Peter Thorne to Cardiff City for a combined fee of £2.7 million and with that money he brought in defender Peter Handyside from Grimsby Town who was made captain, goalkeeper Neil Cutler, Belarusian defender Sergei Shtanyuk, Belgian midfielder Jurgen Vandeurzen, David Rowson from Aberdeen and most impressively former Dutch international Peter Hoekstra.

[5] Stoke went into the second leg at the notoriously hostile Ninian Park 2–1 down and with both sides missing chances the match was 0–0 after 90 minutes and in the final minute of injury time James O'Connor scored to send the match into extra time.

[6] Guðjón signed a contract with Start[7] in Kristiansand just through the end of the season to try to steer the club away from relegation.

In June 2008, the media in Scotland repeatedly linked Guðjón with the manager's post of Heart of Midlothian,[8] with Terry Butcher as his assistant, but Akranes officials insisted it was only rumours and he would stay put in Iceland.

[12] Guðjón was announced as new manager of League One side Crewe Alexandra on 24 December 2008, as a permanent replacement for the recently sacked Steve Holland.

However, previous caretaker manager Dario Gradi remained in charge of the team for two games during the Christmas period, with Guðjón taking over on 29 December.

[13] Despite improvements on the pitch, which saw him win manager of the month for February[14] he could not prevent the club from being relegated into League Two.

[15] In July 2020, he took over as the manager of 1. deild karla club Víkingur Ólafsvík after the firing of Jón Páll Pálmason.

[19][20][21][22] On 13 May 2005, he resigned as manager of Keflavík only a few days before the 2005 season began, because of unfulfilled financial and professional obligations.

[24] Guðjón had repeatedly denied being in talks with English League 2 club Notts County at the time.