After just one start in for the Whites he broke a bone in his foot in February 2007, an injury that ruled him out for the rest of that season, which ended in relegation.
More misery followed with another break in the summer, this time to his other foot, and although the 6ft 2in striker has returned to score three goals this campaign, there is little doubt the injuries had taken their toll.
Flo, who played his final appearance for United in last month's 1-1 draw at home to Crewe, has already returned home to his family in Norway.
Flo told the club website: "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."
He added: "I had two goals this season, one was to get free from injury and the other was to get a regular place in the side. They were both equally important to me, but while I managed to get fit, I did not get a regular place.
"I talked it over with my family. My wife is pregnant and I have been commuting. Now, I will be able to see my three children a lot more."
Flo, who netted 26 goals in 73 appearances for Norway, won the League Cup and the European Cup-winners' Cup during his time with Chelsea.
Gary McAllister paid tribute to Flo after Tuesday's home defeat to Cheltenham, despite only working with him for a few months.
He said: "The time I did work with him here he was first class, but not only a first class professional, also a fantastic player.
"I played against him many times, and during his spell at Chelsea, which was probably his best spell, he was a quality player who was always a threat and I think he's a foreign player that's come into our country and been a success.
"He's a great example for young professionals to look at. He looked after himself, did have a few injuries over the years but worked hard to get himself back fit, and represented his country at the highest level, so I've nothing but admiration for Tore Andre Flo."
Ken Bates, who also worked with Flo at Chelsea, told the club website: "He signed for me at Chelsea as a kid and came to Leeds in our hour of need. My personal thanks go to him. He has been a great player throughout his career and I would like to wish him all the best for the future."
Flo Highlights;
Scored 189 career goals.
Had spells with Chelsea, Sunderland and Rangers.
Became the SPL's most expensive signing when joining Rangers for £14m.