The 85-year-old, who currently serves as an ad hoc judge at the UN's International Court of Justice, drew huge applause and an outpouring of praise for her work over decades - including as an investigator of crimes in Rwanda, Israel and the occupied Palestinian territories and as as a lawyer who helped defend Nelson Mandela.
Israel's foreign ministry criticised the award and said on X: "If there were an award for lies, hatred, and blood libels, Navi Pillay wouldn't just be a contender. She'd be a frontrunner."
Israeli Prime Minister Netanyahu's office condemned the award in a statement on X.
"The Nobel Prize committee has lost its moral compass," it said.
"It has awarded its highest honour to a bigot who built her career around inventing and propagating blood libels against the one and only Jewish state."
In awarding the 125th peace prize, the Norwegian Nobel Committee sought "to remind the world that the rule of law, national and international, underpins the system we have set up to ensure peace and resolve conflicts nonviolently. Peace requires justice," committee chairman Jorgen Watne Frydnes said in announcing the award in Oslo, Norway.
Judges "guard the thin red line between order and chaos," and the world needs jurists "of courage, vision and determination, qualities that Navi Pillay demonstrates in her work on the bench".
In places such as Israel and in apartheid-era South Africa, she and peers took on some of the world's most painful and sensitive legal issues and most vulnerable populations.
Pillay, 85, received the news while attending a forum in Nuremberg, Germany, where the trials of Nazi war criminals helped lay the foundations of international law.
She was in the same room where the trials were held when the prize was announced in Norway.
"Perhaps it was meant to be that I was in this historic Courtroom 600" of the Nuremberg Palace of Justice, she said.
She said efforts to weaken international criminal justice "endanger the progress painstakingly made since Nuremberg, and they risk returning us to a world in which power, rather than law, determines whose suffering matters".
World leaders, she added, have a "legal obligation to protect human rights and refrain from war".
Pillay chaired the Commission of Inquiry on the Occupied Palestinian Territory and Israel, which was created by the UN-backed Human Rights Council.
The commission a year ago concluded Israel was responsible for genocide in the Gaza Strip with a specific intent to destroy Palestinians in the territory.
The Gaza Strip was among Pillay's first comments on Friday after hearing she had won.
"The last thing I did is the delivery of the report on Gaza, naming what's happening there as genocide," Pillay told a crowd gathering to celebrate the award, a video posted on social media by the head of Amnesty International showed.
The commission last year also concluded the Israeli president, prime minister and former defence minister "have incited the commission of genocide".
Israel, which has refused to co-operate with the commission since it was established in 2021, has strenuously denied the accusations.
Pillay has repeatedly rejected critics who accused her of anti-Semitism or turning a blind eye to the Hamas militant attacks in Israel.
Under her leadership, the commission also issued reports accusing Hamas of war crimes and violations of international humanitarian law during its October 7, 2023, attack.
with Reuters
