The 34-year-old has decided now is the ideal juncture to draw the curtain on an illustrious career that encompassed spells in his homeland Norway, Italy, Scotland and England.
Having joined up with Leeds in 2007, he was unable to build on a bright start on his full debut against West Brom, as he proceeded to fracture his foot and missed the remainder of the campaign.
"I had two goals this season, one was to get fit and free from injury, and the other was to get a regular place in the team. They were both equally important to me, but while I managed to get fit I didn't get a regular place," he told the club's official website.
"I talked it over with my family as it is a big decision. My wife is pregnant, I have been commuting, and I will be able to see my three children a lot more.
"I loved my time at Leeds and I just wish I could have been a lot more free of injury. I'd like to thank everyone in and around Leeds for their support. It was great to be a part of the club, and I'm very happy to have played for Leeds United.
"I'm very happy with the career I've had, and I'd like to thank everyone that has been involved at some stage."