Mr Khalilzad is the highest-ranked Muslim in the Bush administration
Having served as America's man in post-invasion Iraq and Afghanistan, Zalmay Khalilzad brings to the UN strong negotiating skills and regional knowledge.
While he comes from a neo-conservative political background, his record in the most challenging areas of US foreign policy has earned him broad respect.
"He is extremely bright, very articulate and very balanced politically - an extremely skilled diplomat," US foreign policy analyst Cliff Kupchan of the Eurasia Group told the BBC News website.
And one major advantage over his predecessor as US ambassador to the UN, John Bolton, is that he "doesn't come with anti-UN baggage", Mr Kupchan says.
But despite not having Mr Bolton's abrasive style, there is no doubting his forcefulness.
During Afghanistan's 2004 presidential election, some candidates complained that Mr Khalilzad was manoeuvring behind the scenes to ensure victory for US favourite Hamid Karzai.
To accusations of excessive meddling, the ambassador would respond with disarming charm: "I'm only here to help."
Zalmay Khalilzad's career in Afghanistan, from November 2003 to June 2005, and subsequent posting to Iraq show he has never been afraid to make Washington's influence felt.
In Kabul, he came to be known as "the viceroy", or the real president of Afghanistan, while as ambassador to Baghdad, he became one of country's most powerful men.
When Iraq struggled to form a new government early in 2006, he warned the US would cut its massive funding if key government posts - specifically the defence and interior ministries - went to "people with a sectarian agenda".
This was seen as a reference to Shia politicians with links to militias, which have been blamed by the Sunni minority for carrying out murders.
Mr Khalilzad quickly realised that bringing Sunnis into the political process was the best way of defeating the insurgency, says the diplomatic editor of The Times, Richard Beeston.
He pursued this policy even though Shia leaders saw it as "a stab in the back", Mr Beeston says.
Mr Khalilzad's influence in Afghanistan was the greater because of his Afghan birth (in 1951) and fluency in the country's two main languages, Pashto and Dari.
Mr Khalilzad had particular influence in his native Afghanistan
He was, says the BBC's former Kabul correspondent Andrew North, totally at home with the wheeling and dealing of Afghan politics.
Alongside his US embassy compound in central Kabul, he had a tent built over the small garden outside, where he could meet key leaders and tribal chiefs in a more traditional style.
Earlier in life, Mr Khalilzad also spent time studying in Lebanon from where he moved to the US with his family in the 1970s and became a US citizen.
The ambassador once worked as an adviser to oil giant Unocal and his detractors linked his oil industry ties to his appointment to Iraq.
They also noted that at the same time that he was working for Unocal, the company was touting for business in Taleban-run Afghanistan.
A Washington insider, he is a neo-conservative with close ties to the Republican party where he followed Vice-President Dick Cheney and former deputy defence secretary Paul Wolfowitz.
Mr Khalilzad was a founder member of the now ailing neo-con Project for the New American Century, and signed its 1998 letter that called on President Bill Clinton to topple Saddam Hussein.
But "when Washington thinks neo-con, Khalilzad is not among the top names which come to mind", Cliff Kupchan says.
"It is my impression that the diplomatic work he has done in Iraq, for instance, will be more prominent a factor at the UN than his political orientation," the foreign policy analyst adds.
As the highest-ranking Muslim to serve in the Bush administration, Zalmay Khalilzad appears well placed to play an even bigger part in US foreign policy as ambassador to the UN.
He would have to be confirmed by the Senate, but analysts say he has maintained good relations with the Democrats.
"I think he is a respected, forceful person," says Cliff Kupchan.
"And as the United States turns to Iran, turns to North Korea and the other hot issues of the day, it seems to me he fits the bill."