The 31-year-old, who ended his playing career in September due to persistent injuries, decided to make the announcement because now was "a good time" for him and because he wanted to promote the discussion of homosexuality in professional sport.
"I'm coming out about my homosexuality because I want to move the discussion about homosexuality among professional sportspeople forwards,'' said Hitzlsperger in an interview which will be published in full in Die Zeit on Thursday.
The midfielder said he has only realised "in the past few years" that he would "prefer to live together with another man'', saying the issue is otherwise taboo inside the dressing room.
"I've never been ashamed of the way I am,'' he added, although he conceded it has not always been easy to live with some of the comments dished out on the subject.
"Just picture 20 men sat around a table together drinking - you've just got to let the majority be, just as long as the jokes are halfway funny and the talk about homosexuality doesn't get too insulting,'' he said.
"In England, Germany or Italy, homosexuality is not taken seriously as an issue, at least not in the dressing room.''
Hitzlsperger's announcement has been supported by his former Germany international team-mate, Lukas Podolski.
The Gunners forward tweeted: "Brave and right decision. Respect, Thomas Hitzlsperger. His outing is a important sign of our time."
Hitzlsperger is the latest sports star to speak about their sexuality in public.
Olympic diver Tom Daley announced in December that he was in a relationship with a man while Surrey and England wicketkeeper Steven Davies, former Wales and British and Irish Lions captain Gareth Thomas, and NBA player John Amaechi have all come out in recent years.
In the world of football, former Leeds midfielder and United States international Robbie Rogers revealed he was gay last February and at the same time confirmed his retirement from football at the age of 25. Four months after that Rogers resumed his playing career by signing for the Los Angeles Galaxy.
Previously, ex-Norwich and Nottingham Forest striker Justin Fashanu came out in 1990. He committed suicide eight years later aged 37.
There were also messages of support for Hitzlsperger on Twitter from his former club Villa as well as from ex-England captain Gary Lineker.
Villa, who Hitzlsperger joined in 2000 before leaving for Stuttgart five years later, said: "Everyone who knows Thomas from his time here at Villa has great respect for him, not only as the fine player he was but also as a man.
"His statement today is a straightforward statement and, along with our support as a club, we hope that everyone involved in the game extends to him their support as well."
Lineker added on his Twitter account: "Congratulations to Thomas Hitzlsperger on bravely being the first player to have played in the PL to 'come out'."
Joey Barton also took to Twitter to voice his opinion on the news in typically uncompromising fashion.
The QPR midfielder tweeted: "Thomas Hitzlsperger has shown a lot of courage today. Sad times when people have to wait till they retire from their chosen profession before they feel other people will judge them solely on who the human being is. Shame on all of us as a society."
Barton also added two further tweets which read: "But it is understandable when brainwashed, religious zealots still believe in a fictional book written over 2000 yrs ago.
"To be religious extremist, you must first be extremely dumb in my opinion. Alex from PSG simply confirms my theory with his comments today."
That final tweet from Barton appeared to be a reaction to comments made by Paris St Germain's former Chelsea defender Alex in a documentary to be broadcast on Canal+ television on Wednesday.
According to Le Parisien, Brazilian Alex discusses homosexuality during the programme about sport and religion, saying: "God wouldn't have created Adam and Eve but Adam and Yves."
While there has been widespread support for Hitzlsperger, the comments made by Alex as well as Michael Johnson's resignation from the Football Association inclusion advisory board are indicative that not everyone is so accepting.
Johnson withdrew from his FA role on Tuesday after footage emerged showing the former player describing homosexuality as "detestable".
Johnson, 40, made the comments in 2012 while appearing on a BBC1 series called 'The Big Questions', during which he opted not to back the FA anti-homophobia campaign.
His remarks were brought back into focus after his appointment to the FA body, although Johnson said last week that his views had changed.
Former Jamaica international Johnson, who played for Notts County, Derby and Birmingham, said he would continue to back anti-discrimination ventures in football.