Burnham has held high office – heading two big government departments under Gordon Brown in 2008 and 2009 – but the world has changed dramatically.
He has warned about the “poisonous” nature of US-style politics and said Trump brought “instability” to the world.
In his victory speech, Burnham urged voters to turn away from the path that “takes us to a divided, dark politics of the kind we see in the United States.”
Experts Weigh In: Charm, Distance, or Deals?
In Washington, longtime watchers of the alliance do not expect a new face to make a difference.
Sidney Blumenthal, former senior adviser to President Bill Clinton, warned: “Prime Minister Andy Burnham will be treated like other British prime ministers by Donald Trump.
The special relationship has been replaced by the abusive relationship.”
“He shouldn't take it personally. Keir Starmer was treated abusively but so was Theresa May.
Trump has very low esteem for British prime ministers and extreme deference to the King of England.”
Burnham has near zero name-recognition in the US – but political strategists and foreign policy experts agreed this clean slate could be an asset.
Frank Luntz, a consultant and pollster, said: “They'll probably think he's a football star. No one in America is going to know who he is.
But that's an opportunity to start afresh.”
Larry Jacobs, professor of political science at the University of Minnesota, added: “Burnham is as unknown a high-level British politician as we've seen in decades.