"After much consideration, lots of time in rehabilitation clinics and after a conversation with both my doctor and physiotherapist, I have decided to end my career," the 34-year-old said in a statement.
"In the last few weeks and months, I have had back problems. After two slipped discs, my body is no longer in the position to cope with the demands of being a professional sportsman."
Having made 82 appearances for Germany, the centre-back's single international goal came in the 4-0 rout of Argentina in the 2010 World Cup quarter-finals.
He was part of the Germany squad at Portugal's Euro 2004, the 2006 World Cup in Germany, Euro 2008 in Austria and Switzerland, plus the World Cup 2010 in South Africa.
He played for Hertha Berlin and Wolfsburg, making more than 200 Bundesliga
appearances before joining North America's MLS league to play for Chicago Fire
"After my own wish, I have cancelled my contract with Chicago Fire and ended my dream career," Friedrich tweeted on Sunday having retired from international football in 2011. "I wish the club and their great fans all the best."
"It has been a fantastic time with unbelievable experiences. I have won many friends in America and in Chicago I have found a second home," he said.