Updated at 10:30 a.m. ET Ford Motor Co. announced Monday that it has replaced President and Chief Executive Officer Mark Fields, who is retiring after nearly 30 years with the automaker. According to Ford's website, Fields' successor is Jim Hackett, who has overseen Ford's efforts on autonomous vehicles as chairman of Ford Smart Mobility. Hackett took that position in March 2016, after serving three years on Ford's board of directors. Previously, he was chief executive of Steelcase, an office furniture company. The management changes became effective Monday. "This is a time of unprecedented change," Executive Chairman Bill Ford said during a conference call. "And time of great change, in my mind, requires a transformational leader. And thankfully we have that in Jim." Ford's stock price has fallen nearly 40 percent since Fields took the reins of the company three years ago.