WASHINGTON — When Rep. Gary Ackerman decided to retire, he did it in the same manner that he served in Congress for the past three decades: on his own terms.

The veteran New York Democrat had insisted for weeks that he would run again, so the announcement of his retirement came as quite a surprise. Redistricting had left him with a viable district — albeit one that shifted his current district straddling the Queens-Nassau County border deeper into Queens — and until right before his announcement he was determined to maintain an open Democratic primary field.

His office’s statement announcing his retirement seemed to suggest that the reason he didn’t bow out sooner was that he wanted to prove he was not leaving scared.

“On the eve of the Federal Circuit Court’s approval of Congressional district lines that were seen to be extraordinarily favorable to Ackerman, and with the primary-free backing of the Democratic Party virtually assured, Ackerman has informed his family, staff, friends and party leaders that he will not seek a 16th term of office,” said the statement from his office on March 16, a day before the court published its approval.

His closest colleagues were taken by surprise.

“I had just spoken to him last week about the new districts, about the machinations,” Rep. Eliot Engel (D-N.Y.) told JTA. “He was sounding like a candidate for re-election.”

Walking out proud was important for Ackerman who, associates say, had been spooked by a major fundraising push against him in the 2010 elections, after he had accepted the endorsement of J Street, the liberal pro-Israel group.

Ackerman handily won that race with 63 percent of the vote, but he told associates that the amount he spent to push back against charges he was weak on Israel was many times the $20,000 he received from J Street.

In January 2011, Ackerman cut off J Street when the group said it could not oppose a proposed U.N. Security Council resolution that would have condemned Israel for its settlement policy.

“The decision to endorse the Palestinian and Arab effort to condemn Israel in the U.N. Security Council is not the choice of a concerned friend trying to help,” he said in a statement severing ties with J Street. “It is rather the befuddled choice of an organization so open-minded about what constitutes support for Israel that its brains have fallen out.”

In fact, J Street had not endorsed the resolution, but had explained why it was not taking a position. But Ackerman’s characteristically sharp turn of phrase garnered more attention than the missed nuance.

Ackerman in a conference call with reporters Tuesday said the pushback for his association with J Street did not unsettle him and that his excoriation of the group was a product of his own tendency to dress down friends. He said he still liked the group.

“I took them rather severely to task — they had made a huge mistake. Friends do not let friends drive drunk, but that does not mean you don’t like them,” he said, borrowing an analogy that J Street’s leaders have used to defend their own criticisms of Israeli policies.

Ackerman first entered the public eye in 1969 when the then-teacher sued the Board of Education for paternity leave — the first father to do so. He then dabbled in newspapering for a while, and in 1979 ran for the New York state Senate. In  1983 he won a special election and launched his congressional career.

He was a dapper presence, sporting a white carnation and wearing light-colored suits — a standout in Congress’ sea of navy blues and blacks. His annual springtime fundraisers in Washington, catered by a Queens deli, were held in rooftops and gardens to live klezmer accompaniment within viewing distance of the Capitol.

Ackerman did not ignore his constituents. He mustered all his influence as a senior Democrat on the House Foreign Affairs Committee to free Ilan Grapel, a former intern in his office whose parents live in his district, after the dual U.S.-Israeli citizen was held in Egypt as a spy in the wake of the chaos following last year’s revolution. Ackerman traveled to Israel to greet the freed Grapel and accompanied him back home to New York.

Ackerman held seats on the House Financial Services and Foreign Affairs committees, but his influence was probably most felt on the latter, where he ascended to senior Democrat on its Middle East and South Asia subcommittee, chairing it from 2007 to 2011.

It was during those years that Ackerman departed from Washington conventions that blamed the Palestinians primarily for the breakdown of the Middle East peace process. He repeatedly wondered aloud whether the Bush administration and by extension Israel had done enough to bolster Mahmoud Abbas after he became the Palestinian Authority prime minister in 2003 and sought support in his turf battle with Yasser Arafat.

At first, Ackerman’s criticisms of Israel were delivered gingerly — an unapologetic partisan, he was happier blaming President George W. Bush for the Palestinian-Israeli impasse than the parties themselves.

But eventually he grew bolder, raising eyebrows in 2009 when he said that Palestinian terrorists and Israeli hardliners were not equivalent “but they are all part of the same destructive fabric.”

At the hearing he convened in February of that year, he described “downward pressure” that “comes from terrorism and the march of settlements. It comes from the firing of rockets and the perpetration of settler pogroms. It comes in daily images of destruction and the constant reiteration ‘that they only understand the language of force.’ ”

Ackerman said Tuesday that he was most touched by a comment by an Israeli in the wake of his retirement — that he had “broken hearts” in Israel with his announcement.

Regarding his criticism of Israel, the veteran lawmaker repeated what he had said about J Street: Friendship is meaningless without honesty.

“If one goes into this business, you can’t go along to get along, you have to call the shots as you see them,” Ackerman said. “Otherwise you’re not necessary. Sometimes it pains friends to hear that.”

His willingness to depart from pro-Israel conventions and his position as the Middle East subcommittee chairman placed him, in 2007, in a position to make history. Ackerman led an effort to ask the Bush administration to increase assistance to the Palestinians from the increments of $20 million they occasionally received in U.S. assistance to $400 million a year.

Condoleezza Rice, then the secretary of state, had solicited the request, recognizing that she needed congressional backing. Ackerman’s role was nonetheless critical. The American Israel Public Affairs Committee backed the hike, in part because the request came from a Jewish pro-Israel leader on the Hill. AIPAC’s support for the added money for the Palestinians lost the lobby the support of one of its major benefactors, the billionaire casino magnate Sheldon Adelson.

Testimonials to Ackerman came in from congressional leaders and from President Obama.

“He was a leader in the fight to pass Wall Street reform and helped strengthen the bonds between the United States and our allies, particularly Israel,” Obama said in a statement. “Gary’s unique enthusiasm will be greatly missed in the halls of Congress, but I am confident he will continue to serve the people of New York for years to come.”

The Wall Street crisis engendered a popular YouTube moment for Ackerman. In 2009, he lambasted the Securities and Exchange Commission officials who had failed to detect the fraud that helped unravel the U.S. economy.

“Your value to us is useless,” he said at a hearing of the House Financial Services Committee. “Your value to the American people is worthless. Your contribution to this proceeding is zero.”

Nobody was spared Ackerman’s anger if he thought they deserved it. He never met an Egyptian official without excoriating the officially sanctioned anti-Semitism in what had been that country’s state-controlled media under longtime President Hosni Mubarak.

The unwillingness to abide evasiveness was a product of his Queens working-class Jewish upbringing, said Engel, who shared a similar background in the Bronx.

“Gary never forgot his roots,” Engel said. “He didn’t grow up in privilege.”

Three Democratic elected officials already have announced that they will run for the now-open Queens congressional seat: City Councilwoman Elizabeth Crowley, Assemblyman Rory Lancman and Assemblywoman Grace Meng. More candidates may still enter the race.

Lancman, who is Jewish and had considered running for the seat, had visited with Ackerman only a few hours before his retirement to promise he would not challenge him. Meng has garnered the support of the Queens Democratic Party and could benefit from the district’s large Asian population.

Asked if he would endorse an Asian candidate, Ackerman — who had earlier recalled his mother’s pride in his election — said he was not going to endorse anyone at this stage but added, “It’s important for a community to have its heroes.”