By Mitra Taj and Teresa Cespedes

LIMA, March 23 (Reuters) - Until this week, Martin Vizcarra led a quiet life as Peru's ambassador to Canada, overseeing the two nations' friendly relations from Ottawa, the Canadian capital.

But Vizcarra also happened to be Peru's first vice president, and he will now swap stately dinners with diplomats for the scorched earth of Peru's presidency, after Pedro Pablo Kuczynski resigned this week under the pressure of graft allegations.

Vizcarra, 55, was sworn in as president of the Andean nation of 32 million people on Friday, promising to fight corruption "at any cost" and calling on lawmakers to end the acrimonious disputes that accompanied Kuczynski's downfall in one of region's most stable economies.

A tall and lanky civil engineer married to a schoolteacher, Vizcarra plunged into politics after seeing his native Moquegua, a small mining region in southern Peru, languish under corrupt local leaders and neglect from policymakers in Lima, the capital.

Inspired by his father, a local mayor, Vizcarra became governor of Moquegua in 2011 and made a name for himself as a good listener and level-headed leader in conflict-prone Peru, the world's No. 2 copper producer.

"He makes decisions when he has to make them, and reflects a lot before doing so," said Luis Marchese, the Peru manager for Anglo American Plc.

Marchese credits Vizcarra with defusing opposition that threatened to derail the company's $3.3 billion proposed mine, Quellaveco. After 20 months of negotiations led by Vizcarra, the company and community leaders reached a deal that modified the project's water-use plan.

But Vizcarra now faces a much taller task.

Kuczynski's epic battle with the opposition-controlled Congress and the far-reaching graft scandal over Odebrecht - a Brazilian builder that admitted to bribing officials in Peru for a decade - has sparked demands for new elections to purge a political class widely seen as corrupt.

"IN TOUCH WITH REALITY"

Vizcarra was in Quebec at a meet-and-greet with Peruvian expatriates on Wednesday when he heard that Kuczynski had resigned in the face of near-certain impeachment, a source close to Vizcarra said. He arrived in Lima after police fired tear gas at protesters marching against the political establishment.

Vizcarra's biggest asset might be his low profile.

He started to distance himself from the government last year as Kuczynski came under fire from the rightwing opposition party that controls Congress.

Unlike Kuczynski, a Princeton-trained former Wall Street banker, Vizcarra tends to watch the Sunday night news shows that often set the week's agenda in Peru and is a more shrewd politician than he appears, the source said.