Hitzlsperger, who lists Aston Villa, Stuttgart and Lazio among his former clubs, retired from football in September 2013 after a short spell with Everton.
With 52 Germany caps to his name, he has become arguably the most high-profile footballer to reveal he is gay - following in the footsteps of lower-league Swedish player Anton Hysen, son of former Sweden international Glenn, and United States winger Robbie Rogers.
And Hitzlsperger, 31, is keen for his announcement to spark a wider discussion about sexuality in all levels of the game.
He told Zeit: "I talk about my homosexuality, because I want to push the discussion about homosexual pro athletes forward.
"In England, Germany and Italy homosexuality is no serious topic, at least not in the dressing room.
"I was never ashamed that I am how I am."
Lukas Podolski was quick to praise his former international team-mate for going public, as he posted on Twitter: "Brave and right decision. Respect, Thomas Hitzlsperger. His outing is a important sign in our time."
Rogers immediately retired from football after coming out, claiming he would not be comfortable around his team-mates, although he has since returned to the professional game with MLS outfit LA Galaxy.
Hysen remains under contract at Swedish third-tier side Utsiktens.
