At Nissan and alliance partner Renault, Palmer's exit adds to an exodus of executives, which began last year with Renault second-in-command Carlos Tavares. Like Palmer, Tavares was seen as a potential future leader and now heads French rival PSA/Peugeot-Citroen.
Infiniti has lost its CEO Johan de Nysschen, who left in July for rival Cadillac, as well as Europe chief Fintan Knight, an Audi and Lamborghini veteran who left in May to become sales and marketing boss at BMW's Rolls-Royce unit.
The loss of Palmer, who joined Nissan in 1995, leaves a big hole as he covered everything from sales and marketing to future product and Infiniti.
"He is the main player on their field. He created the strategy," said Tatsuo Yoshida, an auto analyst at Barclays Securities, Japan. "It’s a loss for Nissan. He knows the Nissan system well, from the old days."
Palmer had a meteoric rise at Nissan, after joining its European technical center in 1991 in Cranfield, England. Last November, he was named Nissan's global No. 3 executive behind Ghosn and Hiroto Saikawa, a Nissan lifer who oversees Asia, r&d, purchasing and manufacturing.
Face of Nissan
Of Nissan's nine executive vice presidents, Palmer has arguably the biggest portfolio and wields the widest influence. He signed off on all things related to product planning, marketing, sales, zero-emission vehicles and was chairman of Infiniti.
And after Ghosn he was the most widely recognized executive, presenting the face of the company at auto shows and product launches from Bhutan to Barcelona.
Among his pet projects: The Nissan Leaf electric car, the NV200 New York City taxi and the push for autonomous vehicles. "I'm the face of the car," Palmer said in an interview last autumn.
Following de Nysschen’s departure, Palmer had been filling in as Infinit's operational head. Nissan has now shifted those duties to Jose Munoz, Nissan’s executive vice president in charge of North America, spokesman Jeff Kuhlman said.
Nissan hasn’t decided on a full-time replacement at Infiniti.
Kuhlman downplayed concern about disruption at Nissan. "I think there is reason to be optimistic this will be a smooth transition," Kuhlman said. "Klein comes in with equal credentials with a wealth of experience."
Like Palmer, Klein is an engineer by training. He starts Sept. 15 at Nissan’s world headquarters in Yokohama, Japan.
It will be Klein’s third stint with Nissan. From 1999 to 2003, he was a Nissan vice president in charge of the CEO office, during the early days of Renault's bailout of then-foundering Nissan. He returned in 2007 and worked corporate administration in the CEO and COO offices for a year before returning to Renault, where he now oversees product planning.
Klein: 'No nonsense engineer'
"He's a no-nonsense engineer," Kuhlman said of Klein, who joined Renault in 1981 on the engine development team.
Klein is a longtime confidant of Ghosn, and was often mentioned as a possible successor as Renault COO to Carlos Tavares, who left the French carmaker in 2013.
“The loss of Andy is huge, but Klein is one of the best people to fill the gap,” Barclay’s Yoshida said.
Palmer's move to Britain positions him to be with family and take the reins of an entire company. He had often been mentioned as a possible successor to Ghosn at Nissan, after spearheading the company’s electric vehicle program and overseeing a global marketing makeover.
During an interview with Automotive News Europe sister publication Automotive News late last year, Palmer said a November management shuffle, which dissolved the COO position and created five direct reports to Ghosn, showed there were plenty of choices to lead Nissan in the future. Regarding his own rise at the company, he said: "At some point, there's no room on the ladder."
Reuters contributed to this report