When talks to end the Russia-Ukraine war took an unexpected turn last week, with the leak of a peace plan said to come from the US, the Trump administration dispatched an unlikely figure to attend a flurry of overseas meetings.
The youngest-ever army secretary, 39-year-old Dan Driscoll is often referred to as President Donald Trump's drone guy for his embrace of emerging battlefield technologies. Until recently, he was mostly known for discussions of budgets, supplies and staff issues in the military's largest branch.
Driscoll does not appear to have a long history of dealing with Russia and Ukraine, or experience in international diplomacy, and has never held public office.
So, who is this increasingly prominent figure within the administration?
Close ally of Vice-President JD Vance
It is Driscoll's relationship with the now-vice president, JD Vance, that brought him into Trump's orbit.
Like his friend Vance, Driscoll attended a public university before joining the US Army, and then earned his law degree at the prestigious Yale University. Both men also worked in finance after graduating.
During his military career, Driscoll became an officer in 2007, led a cavalry platoon and deployed to Iraq for several months in 2009.
He has told the story of meeting Vance through a veterans' student group at law school, during which Vance reassured new students that they would at first feel as if they did not belong, but would excel at classes after a few months. Soon, Vance became Driscoll's friend and mentor.
Driscoll was on holiday with his family in Switzerland in the summer of 2024 when Vance called to tell him he was going to be Trump's running mate and asked him to join the campaign.
The next day, Driscoll flew back to the US, bought a suit at an outlet mall, and took an Uber to the Republican National Convention, he told the alumni magazine for the University of North Carolina, Chapel Hill - the institution where he was an undergraduate.
Once Trump returned to office, Driscoll was swiftly approved as army secretary in his Senate confirmation vote. His sphere of influence expanded after he became a key figure in Trump's deployment of the National Guard to US cities. Afterwards, he also took over the role of acting director of the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Unannounced visit to Ukraine
Driscoll has often spoken about the war in Ukraine - pointing to Ukrainian drones as a relatively cheap, mass-produced technology that is good for fighting.
But after being nominated for the army secretary job, he did not initially appear to be involved in negotiations to end the war. Trump was instead relying on his special envoy, Steve Witkoff, to work on a plan for a ceasefire.
When details of a 28-point plan drafted by the US and Russia were leaked last week, Ukraine immediately voiced concern at some of its key points - and its European allies followed suit.
Driscoll then made an unannounced visit to Ukraine along with other high-ranking Pentagon figures, the most senior military group to travel to Kyiv since Trump took office in January. The purpose, according to a US Army spokesman, was to meet Ukrainian officials and discuss efforts to end the war.
Driscoll met Zelensky and was then, according to Politico, feted at a reception at the US ambassador's residence.
In subsequent days, Driscoll participated in more discussions with Ukrainian officials in Geneva alongside Secretary of State Marco Rubio, Witkoff and Trump's son-in-law Jared Kushner, and helped draw up an updated and refined peace framework.
He went on to hold talks with Russian officials in Abu Dhabi, according to CBS News.
A future envoy... or defense secretary?
In nominating Driscoll as his army secretary, Trump wrote he had a powerful combination of experiences to serve as a disruptor and change agent.
Some in Washington are wondering if those qualities and his recent appearance on the world stage mean that Driscoll could one day replace Pete Hegseth, if Hegseth ever steps down as defense secretary.
While he has never held public office, Driscoll worked in Congress as an intern for the Senate's veteran affairs committee, and in 2020 he made an unsuccessful bid for a House seat in North Carolina. A former professor has suggested Driscoll aimed to serve in the military, go to law school and be in politics.
There is also the possibility Driscoll could step officially into the role of negotiating with Ukraine when Trump's special envoy to the country, Keith Kellogg, leaves in January.
Or he could stay as the head of hundreds of thousands of troops in the US Army. Driscoll has previously highlighted that his father and grandfather served in the military before him, and he often speaks about his vision of transforming the Army.
Days before heading to Ukraine, Driscoll described how he imagined the near future, when every infantryman...will carry a drone into battle and soldiers would rely on artificial intelligence to keep pace with modern warfare. Our window to change is right now, he said in a speech in October. And we will win with silicon and software, not our soldiers' blood and bodies.
