The 31-year-old retired footballer came out in a newspaper interview on Wednesday, saying he did so in order to “have a public debate about homosexuality” among professional sportsmen.
Hitzlsperger - who in addition to Lazio also played for clubs in both the German Bundesliga and the English Premier League - said that homosexuality is not seen as a “serious issue, at least not in the changing room".
"It was not always easy to sit on a table with 20 young men and listen to jokes about gays," he told Germany’s Zeit newspaper.
Responding to the news, Rome’s Gay Center said Hitzlsperger’s announcement should be seen as an opportunity for Italy’s gay footballers to come out.
“Are there gay players in Italy? We think so. They should do as Hitzlsperger and state it publicly,” the organization said in a statement.
Sports stars coming out "would be a positive message, above all for young people, which would help combat homophobia," the Gay Center said.
Hitzlsperger played for Lazio in 2010, before moving to London to play for West Ham United. The former Germany player also had stints at Premiership clubs Aston Villa and Everton and a number of teams in his home country. He retired from football in September, due to a knee injury.