From South Africa to London, condolences streamed out from the world's capitols.
But it is arguably across the British Isles that Kennedy's death resonated the most, with both current and former leaders praising the Irish-American for his role in bringing peace to Northern Ireland.
Descendants of Irish immigrants, Kennedy and his brothers John and Robert drew large crowds of admirers whenever they visited Ireland.
Click here for ABC News' full coverage of Kennedy's death.
British Prime Minister Gordon Brown today hailed the man he called "the Senator of Senators," saying "Sen. Edward Kennedy will be mourned not just in America but in every continent."
Britain honored Kennedy with a knighthood in March of this year.
"Northern Ireland today is at peace, more Americans have health care, children around the world are going to school. And for all these things, we owe a great debt to the life, and courage, of Sen. Edward Kennedy." Brown said in a tribute earlier this year during a speech before a joint session of Congress in Washington.
Former British Prime Minister Tony Blair said today that Kennedy was "a figure who inspired admiration, respect and devotion, not just in America but around the world."
"I saw his focus and determination firsthand in Northern Ireland, where his passionate commitment was matched with a practical understanding of what needed to be done to bring about peace and to sustain it," Blair recalled. "I was delighted he could join us in Belfast the day devolved government was restored."
Irish Prime Minister Brian Cowen described Kennedy as "a great friend of Ireland," thanking him for using "his considerable influence in the world's most powerful parliament for the betterment of this island."
'In good days and bad," Cowen said, "Ted Kennedy worked valiantly for the cause of peace on this island....Today, America has lost a great and respected statesman and Ireland has lost a long-standing and true friend."
Kennedy Hailed as American Icon Who Fought Apartheid
In Australia, Prime Minister Kevin Rudd said Kennedy "made an extraordinary contribution to American politics, an extraordinary contribution to America's role in the world."
Condolences poured in from as far afield as South Africa, where Achmat Dangor, the C.E.O. of the Nelson Mandela Foundation, praised Kennedy for championing "democracy and civil rights."
He "made his voice heard in the struggle against apartheid at a time when the freedom struggle was not widely supported in the West," Dangor said.
Israeli Prime Minister Binyamin Netanyahu said Kennedy was "a great American patriot, a great champion of a better world, a great friend of Israel. He will be sorely missed."
Italian President Giorgio Napolitano described Kennedy as "a great protagonist of American public life" and "a constant defender of that democratic balance and the guarantees of freedom which have given strength and prestige to his country."
Kennedy, Napolitano said, "left a profound mark" on the world in the course of his career and "deserves the homage of the free world" for his contribution.
A Legacy of Working for Peace in Northern Ireland
Former Irish Prime Minister Bertie Ahern, who worked closely on the negotiations leading to the Good Friday agreement in Northern Ireland, said Kennedy "lived to see two great chasms bridged, between Catholic and Protestant in Northern Ireland and between black and white in his own United States."
"These achievements, which were the dreams imagined by his brothers in his youth, were the legacy of a long life and of a good and great man who, no matter how often he stumbled or the cause stalled, continued with a tenacity and a great belief that was the hallmark of everything he did and of the man he was," Ahern said in statement.
Irish President Mary McAleese said Kennedy would be remembered "as a hugely important friend to this country during the very difficult times."
McAleese hailed Kennedy for making an "outstanding and remarkable personal contribution" to Ireland, "despite the sacrifice and sorrow that was part of the overall contribution of the entire Kennedy family," adding that his death would be "greeted with a great sense of sadness here."
These sentiments were echoed by Irish Foreign Affairs Minister Micheal Martin, who said Kennedy was "the embodiment of the Irish immigrant story," and that Ireland owed him "a particular debt of gratitude ? for always being a true and loyal friend and steadfast supporter."
"He was, to the very end, a true profile in courage," Martin said.