Keir Starmer declared that Labour has "closed the door on anti-Semitism" and ended a "dark chapter" in the party's history.
The Labour leader expressed delight as members backed a package of reforms at Labour's conference in Brighton, including a fully independent complaints process to tackle anti-Jewish hate.
Members overwhelmingly backed rule changes proposed by the equalities watchdog, which found Labour had broken the law over its handling of anti-Semitism complaints.
Labour published its plan for a major overhaul in response to the damning report by the Equalities and Human Right Commission (EHRC) into anti-Jewish hate in Labour ranks last year.
At a reception for party activists, Mr Starmer said: "We have closed the door this evening to anti-Semitism in the Labour Party.
"We've turned our back on the dark chapter.
"Having closed that door, that door will never be opened again in our Labour Party to anti-Semitism.
"We will be an inclusive, open, tolerant Labour Party proudly facing our country, proudly facing the world."
The Board of Deputies of British Jews welcomed the new approach.
Board of Deputies president Marie van der Zyl said: "The result shows that Labour is on its way to banishing the anti-Semitism spectre that has hung over it for the past few years.
"While there is clearly still work to do, Labour must continue to demonstrate that it will not allow British Jews to feel marginalised in the party again."
Former Labour MP Ruth Smeeth, from the Jewish Labour Movement, told delegates she felt "sick" being in Brighton as she feared receiving more abuse.
But she struck a defiant tone as she insisted the party is "turning the page on the blight of anti-Semitism that has infected" the party, adding to the abusers: "You failed. We're still here."
Ms Smeeth told delegates: "I stand here with mixed emotions.
"Relief that we can finally turn the page on the blight of anti-Semitism that has infected our party. Anger that it has taken five years to get here.
"Disbelief that despite the hurt of so many Jewish members, there are people in here today who say it was all a smear.
"And sorrow that so many wonderful friends were forced to choose between their faith and their politics."
Ms Smeeth said this was her 22nd year at Labour Party conference, adding: "And yet I feel sick at the idea of being in Brighton knowing that I will be a target for more racist abuse for being here.
"But I'm here to help deliver the promise that Keir made when he became leader.
"He promised the country he would root out the anti-Semitism that has infected our party and end the anti-Jewish hate which undermines the values we were founded to protect.
"It breaks my heart that racists thought they had a place in the Labour Party, that Jewish members, usually women, were threatened, abused and bullied every day not by the BNP or the EDL but by those who claimed to share our values."
Ms Smeeth added: "These racists tried to break Jewish members, to hound us out of our party and to scare us into silence.
"Well conference, I have news for them: you failed."
Labour former minister Dame Margaret Hodge said there was "enormous relief and immeasurable hope to every Labour Party member who has been a victim of vile anti-Jew hate".
She added: "My message is simple: never again. Never again can anti-Jew racism pollute our party.
"Never again can we become a hostile environment for Jews.
"Never again can the complaints process be manipulated with serious complaints ignored and victims silenced."
After Dame Margaret finished her speech, a shout of "apology for Palestinians" could be heard in the hall with Mr Ferguson warning members to be respectful during the debate.
Earlier, members also backed Mr Starmer's controversial changes to the party rulebook, which have angered some on the party's left wing.
Leadership candidates will now need the backing of 20% of MPs, or 40 on current numbers, to get onto the ballot paper.
A scheme for registered supporters will be abandoned.
And the bar for which MPs can face deselection will be raised from a third of members or trade unions/affiliates to half of both groups.
