Profile: General James Jones
The departing US national security adviser was the first general in the role since Colin Powell in 1987.
James Jones is a much-decorated 66-year-old retired marine who served as Nato's supreme commander from 2003 to 2006.
His appointment to the top national security post was interpreted by some observers as an attempt by President Barack Obama to reassure military leaders, some of whom had been unnerved by his policy of scaling down troop levels in Iraq.
Gen Jones was believed to share Mr Obama's view that the war in Iraq had caused the US to take its eye off the ball in Afghanistan.
But he has lasted less than two years in the post, a significantly shorter period than his five predecessors.
His departure had been widely predicted in the media, accompanied by suggestions that his personality had never fitted into Mr Obama's coterie of advisers and officials.
As national security adviser, the general had an office in the White House and he would have met with the president on a regular basis.
At the time of his appointment, it was noted in the press that he got on well with Secretary of State Hillary Clinton, and had even hired some of her former staff to work with him on the energy task force he ran in the US Chamber of Commerce.
But his relationship with other figures in the White House was widely reported to be not so good.
Gen Jones had a strong connection with Europe even before he took up his posting (on the recommendation of former Defence Secretary Donald Rumsfeld) as Nato's supreme commander.
"I lived in France for 15 years [aged three to 18] and I feel culturally at home in Europe, whether it's France, Belgium, Spain, Italy, Germany. I've been in all those places as a young person," he told the BBC in 2003.
He still speaks fluent French.
During his time at Nato, he helped to re-shape the alliance to face the "insidious, elusive threats" of the 21st Century - threats that can come from anywhere, not necessarily within Nato's old geographical remit, nor from any particular nation-state.
This included the launch of the first Nato rapid reaction force - a group of up to 2,000 troops capable of responding at a moment's notice to a crisis.
In 2007, he was appointed by the Bush administration as a special envoy for Middle East security.
Prior to that he was chairman of a US congressional commission that investigated the capabilities of the Iraqi police and armed forces.
He also travelled to Afghanistan on fact-finding missions for the Department of Defense.
Gen Jones was commandant of the Marine Corps from 1999 to 2003.
Early in his career he was posted to Vietnam (1967-68) and Japan (1974-75).
He ran an operation providing aid to Kurds fleeing northern Iraq in 1991, in the wake of the first US invasion of Iraq.
Between 1992 and 1994 he was chief of staff for the operation to airlift aid to the besieged population of Sarajevo.