DETROIT – Mary Barra, General Motors new CEO, is not the type of boss who ever thought she’d be featured in Fortune, let alone sit atop the magazine’s inaugural Most Powerful Women in global business ranking. The first woman in her family to go to college, she worked her way through General Motors Institute (now Kettering University) as an engineering intern at a Pontiac factory – the same brand of car that her dad had worked on during his 39 years as a diemaker.

She made it into a fast-track training program, got a GM fellowship to Stanford (MBA, ’90), and went on to master diverse jobs — assistant to CEO Jack Smith; assembly plant manager; vice president of global manufacturing engineering; HR chief; head of global product development, purchasing, and supply chain – with low-ego finesse and the courage to shake things up. As HR boss after GM’s bankruptcy filing in 2009, Barra simplified employee rules and boiled the company’s 10-page dress code down to two words: “Dress appropriately.” As product chief, she got involved in restructuring Opel in Europe, and she pushed GM to build better vehicles on fewer platforms.

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