The person didn't want to be identified because a formal announcement hasn't been made. An announcement is expected later Tuesday.
Barra currently holds what many say is the most important job in the company — senior vice president for global product development. She's in charge of design, engineering and quality of all of GM's vehicles across the globe and has shepherded most of the company's recent new vehicle introductions.
The 51-year-old Barra also heads purchasing and had previously ran the company's human resources operations.
Barra started with GM as an electrical engineering co-op student in 1980 when she attended Kettering University in nearby Flint. She also served as a plant manager and executive director of engineering. She holds a master's degree in business administration from Stanford University.
It was unclear exactly when the leadership transition would take place. Akerson, the company's chairman and CEO, turned 65 in October and said early in the year that he expected to be with the company at least for another year. It's also unclear if GM will separate its chairman and CEO jobs with the change in leadership.
Barra had been among four internal candidates for the position, including Chief Financial Officer Dan Ammann, North American President Mark Reuss and Vice Chairman Steve Girsky.