John Kerry first gained national attention as a decorated Vietnam veteran who became a leader in the political movement against the war in which he was wounded three times, DPA reported.
A Yale University graduate who volunteered for the Navy at a time when few Ivy Leaguers were interested in the military, he saw heavy action leading patrol boats during two tours. After leaving active duty, Kerry joined Vietnam Veterans Against the War and was called to testify to the Senate Foreign Relations Committee in April 1971.
"How do you ask a man to be the last man to die for a mistake?" Kerry, then 27, asked during riveting testimony that led to numerous national media appearances.
More than 40 years later, he was back Thursday in the Senate Foreign Relations Committee, getting a mostly friendly reception for his nomination, announced last month by President Barack Obama, to head the US State Department.
Kerry is expected to easily win confirmation from the 100-member Senate to succeed Secretary of State Hillary Clinton, who plans to return to private life after holding the top diplomatic post throughout Obama's first four-year term.
In the decades since his first appearance at the Senate committee's witness table, Kerry has spent countless hours in the same hearing room as a member of the Foreign Relations Committee throughout his 28 years in the Senate, including as chairman of the panel since 2009.
"John's entire life has prepared him for this role," Obama said when he introduced Kerry last month as his nominee for the top cabinet post.
Kerry's family spent part of his childhood living in post-war Europe, where his father was posted as a career diplomat.
"If you confirm me, I would take office as secretary proud that the Senate is in my blood, but equally proud that so, too, is the foreign service," Kerry said Thursday, pausing as his face twisted and his voice choked with emotion.
"My father's work under presidents both Democrat and Republican took me and my siblings around the world for a personal journey that brought home the sacrifices and the commitment the men and women of the foreign service make every day on behalf of America," the senator from Massachusetts said.
"I wish everyone in the country could see and understand firsthand the devotion, loyalty, amazingly hard and often dangerous work that the diplomats on the front lines do for our nation."
In September, Christopher Stevens, ambassador to post-revolution Libya, and three other US staffers were killed in an attack on a consulate in Benghazi.
The Obama government's handling of the attack has been hotly debated, and Clinton gave confrontational testimony Wednesday in the same Senate Foreign Relations Committee on the Benghazi incident.
Back before the committee on Thursday to speak on Kerry's behalf Clinton said he "has a view of the world that he has acted on, first as that young, returning veteran from Vietnam who appeared before this committee, through the time that he served with such distinction as its chairman."
Tennessee Senator Bob Corker, a conservative Republican, praised Kerry during Thursday's hearing as "someone who's almost lived their entire life, if you will, for this moment of being able to serve in this capacity."
"There's no one in the United States Senate that has spent more time than you have on issues of importance to our country," Corker told Kerry. "The experience you develop while being on this committee and spending time abroad with world leaders ... - there's almost no one who spent that kind of time and effort."
In the Senate, Kerry helped uncover the Iran-Contra scandal in the 1980s, and in the 1990s worked with conservative Republican Senator John McCain, who had been a prisoner of war in North Vietnam, to resolve prisoner-of-war issues with and reopen diplomatic relations with Vietnam.
In Congress, he has served other committees including commerce and finance. Since his 2004 presidential bid, when he won the left-leaning Democratic Party's nomination but narrowly lost to Republican incumbent George W Bush, Kerry renewed his foreign policy focus.
As committee chairman, Kerry has been active in policy toward Afghanistan and Pakistan, strongly engaged on Sudan and South Sudan and helped push through the New START nuclear arms reduction treaty with Russia, which the Senate ratified in December 2010.