Prime Minister Stephen Harper meets with Gary Doer, Canada's new ambassador-designate to the United States, on Parliament Hill in Ottawa on Friday. (Adrian Wyld/Canadian Press)Gary Doer was introduced Friday in Ottawa as Canada's next ambassador to the United States, a day after surprising many political observers by announcing he was stepping down as premier of Manitoba.

"I was really honoured to have the offer, and I really appreciate being the ambassador-designate," he told reporters shortly after a morning meeting with Prime Minister Stephen Harper.

"So this will be the first time in my life I have to be diplomatic," said Doer, a 61-year-old Winnipegger.

Doer was cagey about when he was specifically asked to take on his new role, saying he had a conversation with Harper over the last couple months.

“It was a conversation about due diligence.”

CBC News learned, however, that the decision to name Doer to the Washington position was made a few weeks ago.

Doer said in 2007 he had also discussed with Harper about moving on after 10 years as premier, the precise length of time Doer has been in his job.

The Manitoba premier's appointment still has to be approved by the U.S. government, but that is considered a formality.

Questioned about how he can reconcile his NDP views with a Conservative prime minister, Doer said the public is not interested in partisan politics when politicians are working for the best interest of Canada.

“The public actually wants all of us from different political parties to compete when we’re in election campaigns and work together in the public interest after a campaign.”

He said he has a history of working with people from all political parties.

'Very important challenge'

Earlier, Harper congratulated Doer on the successful conclusion of his political career in Manitoba and hailed him as a "strong advocate" for good relationships with the United States.

"Look forward to seeing you in Washington," Harper said.

The longtime NDP premier thanked the prime minister, saying he recognized the position is a "very important challenge."

"I know I am part of a great Canadian team," he said during a photo opportunity with Harper.

Michael Wilson, the current ambassador and a former Conservative finance minister, has been in the post since March 2006.

'Not going to be watching soaps'

Doer was coy about his future plans when he announced his resignation as Manitoba's 20th premier.

"What am I going to next? Well, I'm not going to be watching soaps," he almost giddily told his news conference.

Doer did not provide the exact date of his resignation, saying only it would likely be in the fall after being decided in consultation with his party.

At his announcement Thursday, Doer said he wanted to go out on his own terms and felt it was a good time. Sources told CBC News that Doer wanted his resignation to be announced in his own city, in front of Manitobans, and not as part of a bigger announcement.

Doer is following the career path of former New Brunswick premier Frank McKenna.

The Liberal politician also stepped down on his 10th anniversary of becoming premier, and then went on to represent Canada in the United States.

"It's a great job for a former politician," McKenna told CBC News. "They understand how politics works. Someone like Gary Doer has great diplomatic sense, and I think he'd be a great fit with the back channels and social scene down there."

With files from Karen Pauls and Julie Van Dusen