Butterfield, 52, is being replaced by J.H. Lee, who was senior executive vice president of Kia Motors Corp.
Kia Motors America also named Len Hunt, 50, former head of Volkswagen of America Inc., as COO.
The details behind Butterfield's sudden departure were not immediately available.
Hunt, who will join Kia at its Irvine, Calif., headquarters on Monday, Oct. 10, will report to Lee.
News of Hunt's resignation from Volkswagen AG surfaced on Thursday, Oct. 6. He had been set to become board member for sales and marketing at Bentley Motors Group, the VW Group's British luxury-car maker in Crewe, England.
In September, VW named Adrian Hallmark, 43, to replace Hunt as executive vice president in charge of the VW brand in North America.
Hunt will be responsible for overseeing all Kia Motors America business operations, including sales and marketing, fixed operations and corporate planning, Kia said.
In a prepared statement, Lee said: "Kia Motors is entering a new phase of aggressive growth in the United States, and we have realigned our management structure to better support this effort. With his experience and industry track record, we welcome Len to Kia and look forward to his leadership during this critical period of brand development in the U.S."
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