General Motors has elevated Mary Barra as its new CEO to replace Dan Akerson, making her the first female to head a global automotive manufacturer.

Barra, 51, had served as GM's executive vice president of global product development, purchasing and supply chain. Barra also joins the GM Board of Directors.

Akerson's retirement, effective Jan. 15, marks the end of an era for GM as the automaker has emerged from federal ownership of the company. On Monday, the U.S. Treasury sold its remaining GM shares.

GM announced several other executive moves Tuesday, including appointing Theodore "Tim" Solso, former chairman and CEO of Cummins, Inc., as GM chairman. Dan Ammann was elevated to company president from executive vice president and chief financial officer.

Mark Reuss fills Barra's former role and Alan Batey replaces Reuss, who had served as executive vice president and president of North America. Steve Girsky will move to a senior adviser role until he leaves the company in April.

Akeson, 65, had planned to step down, but accelerated his succession plan after his wife was diagnosed with an advanced stage of cancer.