State Senator Thomas K. Duane, who first burst onto the political scene two decades ago, when he disclosed during a successful bid for City Council that he was H.I.V. positive, and later made his mark as the first openly gay member of the Senate, has decided not to seek re-election.
On Monday, Mr. Duane, a Democrat, will announce his decision to call it quits, opening up the seat in a district that stretches from the Upper West Side to Greenwich Village, and across to the East Village.
No, it is not his health. No, he does not have another job lined up. And no, Mr. Duane said cheerfully in an interview, he has not done anything illegal or embarrassing that is about to make news.
Instead, Mr. Duane, 57, said that he had simply tired of ricocheting between the city and Albany, as he has for nearly 14 years - a number he repeated at least a dozen times - and that he was eager to try something new.
“It’s not that Albany isn’t a lovely place, but it’s not home,” he said. “I always knew that I was going to have another chapter in my life, and it’s time for me to start that new chapter.”
Mr. Duane, who was a pivotal figure during the recent battle over same-sex marriage, said that he had only begun to think seriously about retiring a few weeks ago, around the time that he and his longtime partner, Louis Webre, attended the wedding of Christine C. Quinn, the City Council speaker and his former chief of staff, and Kim M. Catullo.
Mr. Duane said he did not know what he would do after his term ends on Dec. 31. But he did rule out becoming a lobbyist, and said he had no plans to run for office again.
“I am going to fight for people and in my own small way try to make the world a better place,” he said. “I’m never going to stop doing that.”
With Republicans now holding a slim majority in the Senate, Mr. Duane’s departure is unlikely to alter Albany’s balance of power, since whoever wins the Democratic primary on Sept. 13 will be an overwhelming favorite in November.
The shortlist could include State Assembly members Deborah J. Glick and Brian Kavanaugh. Other possibilities are Brad Hoylman and Corey Johnson, the chairmen of Community Boards 2 and 4.
Mr. Duane, a native New Yorker who grew up in Flushing, Queens, first joined the family business as a Wall Street stockbroker. But he drifted into public service, volunteering for his community board and working for Elizabeth Holtzman, then city comptroller.
Mr. Duane became one of the first two openly gay members elected to the City Council in 1991, when, with Ms. Quinn as his campaign manager, he fended off Liz Abzug, the daughter of the feminist icon Bella Abzug. The race was a heated one, in which Liz Abzug declared that she was a lesbian, Mr. Duane announced that he was H.I.V. positive, and each side accused the other of crass politics.
After losing to Jerrold Nadler in a Congressional primary in 1994, Mr. Duane was elected to the State Senate in 1998. Among his signature achievements are bipartisan efforts to close loopholes for people trying to avoid child- and spousal-support payments; a requirement that health insurance plans cover treatment for mental illness; the addition of sexual orientation to the list of protected categories in state laws; and the improvement of medical and mental health care for prisoners. He is also known as a fierce advocate for tenants’ and civil rights.
The loquacious Mr. Duane is also well known for taking the oral equivalent of the scenic route, with lots of detours, when talking about policy issues, and even when discussing his previous addiction to alcohol and drugs.
He came under a glaring spotlight during the initial, failed attempt to pass same-sex marriage legislation, highlighted by a heartfelt if rambling 21-minute speech in 2009 on the Senate floor.
One top gay rights leader complained to the news media that Mr. Duane had been all talk and little action, and that his meandering speech left people “concerned about his leadership on other issues.”
But Mr. Duane bounced back during last year’s successful push for same-sex marriage, and he was present when Gov. Andrew M. Cuomo signed the bill.
In an interview, Ms. Quinn said Mr. Duane had inspired countless gay men and lesbians around the country. He was such a pioneer, she said, that friends had joked that, in virtually every article about him, “ ‘Who Was Gay’ was his middle name.”
But as he racked up legislative victories, she said, “that began to fade away, and he showed that you can be exactly who you are, and be respected and looked to beyond L.G.B.T. issues.”