Greeted by loud, raucous and sustained applause from a large crowd in the building's ceremonial main entrance, Kerry thanked department employees for their dedication.
"We did really good diplomacy," he said, citing what he called numerous significant achievements in fighting the Islamic State group, addressing climate change, sealing the Iran nuclear deal, prioritizing Asia-Pacific relations, supporting European allies and making Russia accountable for its actions in Ukraine.
Kerry, who set a record for miles traveled during his four-year tenure as America's 68th top diplomat, thanked President Barack Obama for the privilege of serving, saying Obama had given him wide latitude to take risks in negotiating agreements or trying to start them.
"I want you to stay faithful to the notion that this building, all of you, that we together are going to continue to make ripples," he said. "We are going to continue to make ripples to sweep down walls of resistance to peace and justice and a better and safer world."
President-elect Donald Trump has assailed much of Obama's foreign policy record. Kerry said global turbulence was not due to any failure in leadership but was rather the result of profound transitions the world and its population are going through.
In an opinion piece published in The New York Times on Thursday, Kerry wrote: "My hope is that the turbulence still evident in the world does not obscure the extraordinary gains that diplomacy has made on President Obama's watch or lead to the abandonment of approaches that have served our nation well."
Kerry also criticized Trump's penchant for tweeting controversial statements.
"Diplomacy requires creativity, patience and commitment to a steady grind, often away from the spotlight," Kerry wrote. "Results are rarely immediate or reducible to 140-character bites. But it has helped build a world our ancestors would envy - a world in which children in most places are more likely than ever before to be born healthy, to receive an education and to live free from extreme poverty."
Kerry logged more than 1.4 million miles in the air over 596 days of travel, the State Department said.
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