Famous Dave's CEO suite got another sudden shake-up Monday, just 16 months after the last one.

The restaurant company's chief executive officer, John Gilbert — who has led Famous Dave's since October 2012 — resigned abruptly and will be succeeded on an interim basis by a recently appointed board member.

Ed Rensi, a former McDonald's executive who later founded the Tom & Eddie's restaurant chain and joined the Famous Dave's board last month, will take over immediately, the company said.

Gilbert, too, was a Famous Dave's board member when he became CEO. He formerly was CEO of e-commerce retailer Vermont Teddy Bear Co., and was known for his marketing acumen.

"It was a surprise to us he resigned," said Dean Riesen, Famous Dave's chairman. "We saw him as a long-term CEO for the next five years plus."

Dick Perkins, whose Wayzata-based Perkins Capital Management owns about 1 percent of Famous Dave's stock, said he, too, was surprised.

Gilbert could not be reached for comment.

He replaced Christopher O'Donnell as CEO in an unusual executive suite shuffle. O'Donnell, who had been Famous Dave's CEO since 2008, has remained with the Minnetonka-based company, serving as its chief operating officer.

Famous Dave's hasn't concluded how it will approach finding a new CEO, Riesen said. But the ability to install Rensi as interim CEO "takes the pressure off of us," he said. "Ed is the right person at the right time now that John has left."

Rensi was president of McDonald's USA from 1984 to 1991 and then CEO of the fast-food giant's U.S. operation through 1997. "He has a great background, a good pedigree," said Mark Smith, a stock analyst at Feltl and Co.

On news of Gilbert's exit, Famous Dave's stock rose $2.67 or 15 percent Monday, closing just shy of a six-year high at $19.95.

Dave's stock was just under $10 when Gilbert took over. It began climbing last June, not long after Famous Dave's cut its corporate staff by close to 15 percent as it worked to get expenses in line with stagnant revenue. Gilbert tried to boost Dave's business through improved marketing, a menu revamp and price increases.

Gilbert's tenure was marked by a buildup in Famous Dave's ownership by potential activist shareholders. Patrick Walsh, who runs Chicago-based PW Partners Atlas Fund, began accumulating his 10.3 percent stake in Dave's at the end of 2012. Walsh was joined in the middle of last year by New York-based Pleasant Lake Partners and Minneapolis' Blue Clay Capital, which own 10.2 percent and 9.7 percent, respectively, according to Bloomberg News.

Minnetonka-based Famous Dave's has been trying to reignite the growth of its restaurant chain, known for its barbecue fare. Sales have been in a holding pattern for the past few years. "It has been a period when revenues have been disappointing," Smith said.

Famous Dave's said Monday it had 2013 revenue of $155.4 million, essentially flat from $155 million in 2012 and $154.8 million in 2011. Income from operations in 2013 was approximately $7.7 million, up about 25 percent over last year.

Business in the fourth quarter was tepid. Comparable sales at Famous Dave's company-owned stores were down 2.6 percent compared with 2013's fourth quarter.

The company is scheduled to announce full fourth-quarter results on Wednesday and said it would keep that schedule.