As the laughter and applause died down, he added, “As the saying goes, I have big heels to fill.” …

Mentioning the cubicle he occupied during the transition between Hillary Rodham Clinton’s tenure and his, Kerry told his new colleagues, “I cannot tell you how great it feels to, sort of, be liberated. . . . I’ve been freed.”

This was true on multiple levels. Kerry, after much striving, was finally where he belonged. At 69, he is in the job he had trained for his whole life — as a diplomat’s son, as a military man, as a young politician in a hurry, as a failed presidential candidate and as chairman of the Senate Foreign Relations Committee. Often rumored to be in line for the post in the past, Kerry was palpably joyful to have the prized assignment.

“This — this is beyond a pleasure,” he told the diplomats.

Not since John Quincy Adams, perhaps, has a man been bred to be secretary of state as John Kerry has. A son of the world and a scion of privilege, he struggled to demonstrate the common touch, mocked in 2004 for his windsurfing and his French. But for this job he’s well-suited, literally: He wore a lustrous blue suit and a salmon-pink tie for his first day; as he was being introduced, he fished in his jacket sleeve for his shirt cuff, making it peek out that perfect half-inch.