During the most important week in North American free trade negotiations last year, Canada’s top representative arrived in Washington wearing white T-shirt that read “Keep Calm and Negotiate Nafta” and “Mama ≠ Chopped Liver”.

The message from her children who made the shirt, was clear: Chrystia Freeland was not to be underestimated.

On Wednesday, the prime minister, Justin Trudeau, elevated Freeland, a former journalist, to the role of deputy prime minister. A largely ceremonial position, the job has not been filled since 2006.

But Trudeau also made her minister of intergovernmental affairs, a job that requires her to manage the increasingly fractious relationship between Canada’s federal government, provinces and territories.

The decision reflects the level of trust Trudeau has in Freeland – and the scale of the task at hand.

In last month’s election, the Liberal party suffered an electoral wipeout in Alberta and Saskatchewan, amid hostility to Trudeau and his legislative efforts against climate change.

A struggling oil and gas sector has hit the economies of both provinces, and anger has begun to fuel a nascent separatist movement – dubbed “Wexit” – that many fear could inflict lasting damage on Canada.

In a parliament in which no party controls a majority, having a close ally to mediate feuds with angry provinces will be critical for Trudeau’s government.

There is no doubt that the portfolio could be “fraught and risky”, said Lori Turnbull, a professor of political science at Dalhousie University.

“[But] because of the national unity issues that are existing now – this should not be seen at all as any kind of a demotion or even a lateral move for Freeland. This is a promotion,” Turnbull said. “Because now it’s clear she’s the one that he trusts the most with the hardest file.”

Freeland was born in a small farming community of Peace River and recently described herself as a “proud Albertan”. She also hails from the Ukrainian diaspora that settled, and has farmed, much of the Canadian prairies for generations.

But those credentials might not be enough to make inroads in a region hostile to Trudeau.

“I mean, she’s still a Liberal,” said Harvey Spak, a retired film-maker in Mundare, Alberta. A member of the Ukrainian community himself, Spak suggested the Liberal brand – and Freeland’s residence in Toronto – would erode any goodwill granted by her background.

But months of tense – and ultimately successful – trade negotiations with the US, have left Freeland battle-tested.

“She’s a big thinker who has a considerable understanding of the international context,” said Roland Paris, an international affairs professor at the University of Ottawa and former Trudeau adviser. “At the same time, she’s a tenacious negotiator.”

Freeland’s meteoric rise from rookie lawmaker to foreign minister and now deputy prime minister has not surprised former colleagues.

“Chrystia was the best in town. She was the person to beat,” said David Hoffman, a former Moscow bureau chief for the Washington Post in the 1990s, who worked alongside Freeland when she ran the Financial Times bureau.

The two travelled the country together, reporting on the growing pains of a region where the rule of law was often non-existent. “I think these were, for her, life-changing events to witness. Because they made us realize how utterly difficult – and how precious – this idea of ‘market democracy’ really was.”

Freeland eventually returned to North America, by way of Toronto and New York, accepting senior editorial positions at the Globe and Mail, the FT and Thomson Reuters.

In 2013, Justin Trudeau, then the newly minted Liberal party leader pursued Freeland, pleading with her to leave media and enter politics, even appearing at her book signing to make his case.

Eventually she accepted his offer to run for federal office in Toronto.

“I think’s she’s, without question, seen as the breakaway star in the Trudeau cabinet,” said Peter Donolo, a political strategist and former director of communications for former prime minister Jean Chrétien.

In her time leading the sprawling foreign affairs portfolio, Freeland cultivated a reputation for blunt charm and a sharply honed ability to read people.

When, during her brief stint as international trade minister, intransigent parties in Belgium held up a huge free trade deal between Canada and Europe, Freeland simply walked away.

Conservatives in Canada were outraged, calling her ploy a “meltdown” and suggesting she needed “adult supervision” on order to effectively negotiate. But the strategy worked, and she closed the multibillion-dollar deal.

“She flipped it over. She did political jiujitsu on it and came away looking like a big winner,” said Donolo.

While feuds within the country will differ from high-stakes international trade negotiations, they will nonetheless occupy a significant amount of Freeland’s energy and attention.

“She’s got a lot of experience in trying to manage diplomacy in extremely complex environments where there are clear and distinct different interests,” said Turnbull.

The position of deputy prime minister is also likely to reignite talk of Freeland as a Liberal party leader-in-waiting. Jean Chrétien remains the only person to have moved from deputy to prime minister, Freeland’s promotion will do little to tamp down speculation.

“I think Freeland would be an obvious choice for a potential successor,” said Turnbull.