Scharner, 33, has stepped away from the game to focus on family life after falling out of favour at the Bundesliga club.
The Austria international – who played at Wigan Athletic and West Brom in the Premier League – joined Hamburg in July 2012, but made just four appearances for the club.
"The end! Thank you for all your support. Bye bye," Scharner's message said.
Scharner's retirement comes just one day after he blasted Hamburg, citing a lack of philosophy and chances for him.
"Hamburg had to pay for their mistakes (in relation to Scharner's payout)," he said.
"From day one, Hamburg had been a disappointment for me. I was never offered a chance.
"Moreover, the club has no philosophy."
Scharner also said that he was growing frustrated with football at the top level, claiming Real Madrid's world-record move to Real Madrid was "wrong".
"Top-level football is no longer about football. It's only business. To pay €100million for one player is just wrong," he said.
"Real characters are no longer in demand."
Scharner's career began at Austria Vienna, while he also spent stints at Red Bull Salzburg and Brann before arriving in England.
