Ryan Crocker became the new US ambassador to Iraq in March 2007, after US President George W Bush made a number of key leadership changes as part of his strategy for the country.
Ryan Crocker succeeded Zalmay Khalilzad as Iraq ambassador
A career diplomat and fluent Arabic-speaker, Mr Crocker has also served as ambassador to Lebanon, Kuwait, Syria and, most recently, Pakistan.
He knows Iraq well, having served in Baghdad in the 1970s, headed the US state department's Iraq-Kuwait Task Force during the first Gulf War, and worked for the Coalition Provisional Authority shortly after the US-led invasion in 2003.
Mr Crocker succeeded Zalmay Khalilzad - appointed the new US permanent representative to the UN - amid a sustained period of unprecedented sectarian violence.
He said then: "It's going to be very, very difficult, but I certainly believe that success is possible or else I wouldn't be standing here."
Testifying to the US Congress several months later, in September 2007, Mr Crocker held to that view.
Iraq was now and would remain for some time to come a "traumatised society", he said.
But, he said: "A secure, stable, democratic Iraq at peace with its neighbours is, in my view, attainable."
Urging the US not to abandon or drastically curtail its presence in Iraq, he warned that while the current course in Iraq was hard, the alternatives were "far worse".
Mr Crocker was born in 1949 in Spokane, eastern Washington state.
As his father worked for the US Air Force, Mr Crocker spent a large part of his childhood abroad and attended schools in Morocco, Turkey, Canada and the US.
He returned to Washington state, however, for his higher education, to study at Whitman College in Walla Walla.
After graduating in 1971 with a BA in English, Mr Crocker joined the Foreign Service. He was first posted overseas a year later, when he worked at the US consulate in Khorramshahr in Iran.
Mr Crocker undertook his first assignment in Iraq in 1979, the same year in which Saddam Hussein became president.
It was also when he first met his wife, Christine, a former secretary in the Foreign Service.
The couple were posted together to Beirut in 1981 at the height of the Lebanese civil war.
They witnessed the Israeli invasion of Lebanon in 1982 and, in 1983, were in the US embassy when a suicide truck bomb exploded outside, killing 63 people. According to the Washington Post, the blast left Mr Crocker "bloodied, but not seriously injured".
His first senior diplomatic posting came seven years later, when he returned to Beirut as US ambassador. He served later as ambassador to Kuwait and Syria.
The ambassador has spent time talking to Baghdad residents
Mr Crocker returned to Washington in August 2001, when he was appointed deputy assistant secretary of state for Near Eastern affairs.
In this role, he made a number of visits to the north of Iraq before the US-led invasion in 2003 to help co-ordinate efforts with Kurdish leaders who also opposed the central government.
After the overthrow of Saddam Hussein, Mr Crocker spent three months as the first director of governance for the Coalition Provisional Authority.
He was responsible for setting up the 25-member Iraqi Governing Council (IGC), which helped the CPA administer Iraq until an interim government was appointed a year later.
In 2004, Mr Crocker became the US ambassador to Pakistan.
While based in Islamabad, he resisted calls in the US to increase pressure on Pakistan's president, Gen Pervez Musharraf, to act decisively against Islamist militants operating near the country's border with Afghanistan.
Instead, Mr Crocker insisted Gen Musharraf was a solid US ally in its "war on terror".
In a news conference marking Mr Crocker's first month in Baghdad, the ambassador said he had been struck by the impact violence had had on Iraq, but nevertheless was impressed by what had been achieved.
"When I left in 2003, there was no constitution, there was no Council of Representatives, there was no sovereign government," he said.
"All of these things are now in place. And I've been impressed by the extent to which Iraqis have stood up to the challenges of building a new state; the courage, the resolve, the dedication they have demonstrated."
Four months later, in August 2007, Mr Crocker told reporters that political progress in Iraq had been "extremely disappointing" but suggested the process of reconciliation was going to take time to trickle down to all levels of society.