Some will take buyouts while others will be laid off.
At the factories, 3,000 workers could lose jobs in Canada and another 3,600 in the US. Other plants making components are at risk of closure as well, along with two factories outside North America.
According to Chiodo, the Oshawa plant has "some of the best employees in North America". In October, nearly 65 percent of new vehicles sold in the USA were trucks or SUVs.
GM's announcement came as a shock to the Trump administration, which has heavily sold itself as protecting American jobs and rebuilding the country's manufacturing base.
The moves are the first big steps in the century-old GM's transformation.
John Henry, the mayor of Oshawa, said early on Monday on Twitter that he hadn't talked to GM yet, and that a meeting was scheduled to begin at 09:30 a.m. Ontario time between the management and workers.
CNN reports that the "company said the plan would make it more efficient, saving $6 billion a year by the end of 2020".
GM is cutting more than 6,300 hourly and salaried workers at its plants and 15 percent of the salaried workers in North America for a total of more than 14,000.
The reductions could ripple through auto parts suppliers such as Aptiv and Magna International, Michaeli said. Barra said the company will double resources dedicated to electric and self-driving vehicles over the next two years.
Barra said GM can reduce annual capital spending by $1.5bn and increase investment in electric and autonomous vehicles and connected vehicle technology because it has largely completed investing in new generations of trucks and sport utility vehicles.
UAW, the autoworkers union, blasted GM's decision, saying the company was just looking for cheaper workers, and vowed to fight back.
GM recently offered buyouts to 18,000 workers.
The company expects to take a pretax charge of $3 billion to $3.8 billion due to the actions, including up to $1.8 billion of asset write downs and pension charges.
The cuts come on the heels of surprisingly strong third-quarter earnings. Most of the affected factories build cars that won't be sold in the US after next year.
GM has internally debated for months how to address shrinking vehicle demand, a person briefed on the matter said, and the issue is certain to re-emerge when GM holds contract talks next year with the United Auto Workers (UAW) union.
The biggest US autoworker union vowed to fight GM's plans. "Get a vehicle that is selling well and put it back in", Trump said.
All of the products now being assembled at those three plants are expected to stop being produced by the end of 2019. It will also stop building models assembled at those plants, including the Chevrolet Cruze, the Cadillac CT6 and the Buick LaCrosse.
The company has "unallocated" production from three vehicle factories (Oshawa, Detroit-Hamtramck and Lordstown), and two engine and transmission plants (Baltimore and Warren) after 2019.
Ontario, home to the Oshawa plant, was told by the automaker that there was nothing it could do to prevent it, premier Doug Ford said.
GM is expected to address union members at the Oshawa plant at 10 a.m.
Democratic Sen. Sherrod Brown called GM's announcement move "corporate greed at its worst".
In Canada, Prime Minster Justin Trudeau expressed "deep disappointment" with the plant closure.