General Motors Co. GM 0.79% is betting its future on electric cars. By mid-decade it plans to spend $27 billion on manufacturing 30 electric models and developing driverless cars. By 2035, it expects to have phased out gasoline-engine options completely and to be selling only electric vehicles, a technology that currently generates about 2% of sales and no profit for the company.

Planning for this transformation at the factory level is the responsibility of Gerald Johnson, a GM lifer who took over global manufacturing operations in 2019, and who is spearheading a $2.2 billion gut rehab of a factory in Detroit, recently renamed Factory Zero, to serve as GM’s electric-vehicle hub. Two more conversions of North American factories for production of electric vehicles, or EVs, are in the works.

Mr. Johnson, 58 years old, calls it the most far-reaching strategic shift he has seen in his career at GM, which he began 40 years ago as an intern. “There has always been incremental change,” he says. “This is transformative.”

GM factories around the world employ more than 100,000 workers. Some plants exist solely to assemble gas-powered engines and transmissions that won’t be needed if the company successfully reaches its 2035 target, portending big changes for both workers and GM’s factory footprint.

Addressing disruption is nothing new to Mr. Johnson, whose duties have included managing labor relations through a bitter 40-day strike at GM’s U.S. factories in 2019 that drained $3.5 billion in profit. Last spring, his team led GM’s effort to make ventilators after Covid-19 hit the U.S., closing car factories for nearly two months. Now, continuing supply-chain disruptions are hampering efforts to make up for lost output.

The Wall Street Journal talked to Mr. Johnson recently. Here are edited excerpts.

WSJ: Electric cars are breaking down some of the barriers to entry that have protected big car companies. How can GM maintain its edge?