Hamrén va jugar a l'equip local del Ljusdal IF abans de començar la seva carrera com a entrenador.
==Coaching career==
Hamrén coached Norwegian team [[Rosenborg BK]] to league championship in his first full season with the club. His previous job was com a entrenador of the [[Danish Superliga]] side [[AaB Football|Aalborg BK]], where he guided the team to a 5th-place finish in the [[2005–06 Danish Superliga|2005–06 season]], a 3rd place in the [[2006–07 Danish Superliga|2006–07 season]], and to the championship in the [[2007–08 Danish Superliga|2007–08 season]].
Following heavy speculation in Swedish and Norwegian media, it was confirmed on 4 novembre 2009 that Hamrén would assume part-time responsibility of the [[Sweden national football team|Swedish national football team]] while also managing Rosenborg, until Rosenborg would relieve him from his contract on 1 setembre 2010.<ref name=Adresseavisen/> From that point, Hamrén would assume full-time responsibilities for the Swedish team.<ref name=Adresseavisen>{{Cite web|url= http://fotball.adressa.no/eliteserien/article154894.ece|publisher=Adresseavisen|title=Hamrén Sverige-klar|date=4 novembre 2009|language=Norwegian}}</ref><ref>{{cite web|url= http://news.bbc.co.uk/sport2/hi/football/internationals/8343497.stm|title= Hamren named as new Sweden coach |date=2009-11-04|work=BBC Sport|accessdate=2009-11-04}}</ref> After heavy discussions with RBK (Erik Hoftun, Terje Svendssen, Nils Skutle, Lars Aune), Hamren eventually was confirmed com a entrenador for the Swedish national team.
On 16 octubre 2012, he presided over a game where the national team finished with a [[2014 FIFA World Cup qualification – UEFA Group C#Germany v Sweden|4–4]] draw from 4–0 down in [[Berlin]] against [[Germany national football team|Germany]] in [[2014 FIFA World Cup qualification – UEFA Group C]]. <ref>{{cite news|first=Philip|last=O'Connor|url= http://www.independent.ie/sport/soccer/swedish-coach-didnt-sleep-following-amazing-fightback-in-germany-3263437.html|title=Swedish coach didn't sleep following amazing fightback in Germany|newspaper=Irish Independent|date=17 octubre 2012|accessdate=17 octubre 2012}}</ref><ref>{{cite news|url= http://www.goal.com/en-gb/news/3841/world-cup-2014/2012/10/17/3456001/the-night-efficiency-died-sweden-collapse-signals-the-end-of?source=breakingnews|title=The night efficiency died: Sweden collapse signals the end of German mental toughness|work=GOAL|date=17 octubre 2012|accessdate=17 octubre 2012}}</ref> Hamrén qualified Sweden for [[UEFA Euro 2012|Euro 2012]] and [[UEFA Euro 2016|Euro 2016]], before stepping down as the manager of Sweden. Currently, he is taking a break from football, and he does not know, whether he will return again.
