For Best Buy CEO, a whole new world

He was unemployed and took the paid-on-commission job after his mother, an employee in the chain’s accounting department, convinced him to give the company a try.

“I wasn’t sure I’d make it through the holiday season that year,’’ he said. “I remember going home with the sore retail feet.’’

Yesterday, almost 24 years after his first day of selling video cassettes and speakers the size of chairs, Dunn became chief executive of Best Buy Co., which has grown to become the world’s largest consumer electronics chain.

“I was there,’’ he said during a speech before shareholders at the company’s annual meeting in suburban Minneapolis. “For the good, the bad, and the ugly, and everything in between. And I remember, and I will insist we remember, the lessons we learned from the challenges and changes along the way.’’

The 49-year-old, who eventually ditched the self-described “Miami Vice’’ look as he moved through the company’s ranks and now has a teenage son who works as one of Best Buy’s ubiquitous “blue shirts,’’ has heady challenges ahead.

Despite the demise of its closest competitor, same-store sales are down for the third straight quarter at his longtime employer. The company’s corporate office has hundreds of empty desks after a voluntary buyout. And heavyweights Amazon.com, Wal-Mart Stores Inc., and Costco Wholesale Corp. all have their sights set on the company’s core business.

“I think he certainly has his hands full,’’ said Morningstar analyst Brady Lemos.

Dunn, whose appointment was announced in January and who until Tuesday was chief operating officer, succeeds retiring CEO Brad Anderson to become the third person to lead the retailer and its 155,000 employees.

Anderson, also a longtime Best Buy employee, became CEO in 2002, along the way managing to almost triple sales, which reached $45 billion at the end of the last fiscal year.

Now, Dunn will try to use that momentum to scoop up more customers from defunct Circuit City Stores Inc. He will also have to execute his four-part plan to keep Best Buy competitive - and able to fend off attacks from retailers hungry for a piece of the company’s sales.

Among them: boosting the chain’s market share in local communities by stocking stores with an assortment of products and smart employees, and amassing so-called connected digital solutions by offering everything from gadgets and accessories to smartphones to digital music, in part through the company’s growing cellphone venture, called Best Buy Mobile, and its recent acquisition of the file-swapping service Napster.

“We’re moving to a time when every device connects to every other device and every human being can connect to every other human being,’’ he said. “We’re moving to an era of ubiquitous connectivity.’’