LOUISVILLE, Ky. — It's barely 9 a.m. on a Monday, but the crowd assembled on the front lawn at Yum! Brands is already whipped into a lather of excitement.

Employees shake cowbells and cheer loudly. Others pound drums, play electric guitars and wave posters. Some wear hats shaped like giant tacos.

David C. Novak, CEO since 2000 and the architect of Yum's over-the-top culture of "customer maniacs," stands in the middle of the chaos with a boyish grin.

"The biggest thing that's made our company a success is that it's been founded on the belief that people make it happen," Novak tells the crowd, gathered to celebrate the Louisville fast-food company's 10th anniversary. "Every single one of us can be a customer maniac."

The scene is classic Yum — overflowing with the kind of enthusiasm that could be found at a high school pep rally.

Executives at the company's headquarters almost never wear ties, and good work often is rewarded with rubber chickens or sets of chattering fake teeth.

Novak, 54, who grew up in a series of trailer parks and never went to business school, describes himself as a tough motivator who uses humor and rewards to "raise the bar" for employee performance.

He cites that leadership philosophy as one of the key reasons for Yum's success in the decade since it was spun off from PepsiCo.

Employee turnover, roughly 200 percent annually a decade ago, has been cut in half. Billions of dollars in debt have been slashed from the balance sheet, and the company's stock recently hit a record high of $39 per share — more than five times its value when it was broken off of PepsiCo 10 years ago.

Yum now has nearly 1 million employees, and it builds more new stores each year — mostly KFC and Pizza Hut restaurants — than McDonald's, Home Depot or Starbucks. Yum also owns the Taco Bell, Long John Silver's and A&W chains.

The company's rapid growth, especially overseas, has helped it to ride out various challenges in the United States — such as criticism from animal-rights groups over chicken slaughtering, the relationship between fast-food and the nation's obesity rate — and more recent hurdles such as a video of rats scurrying across the floor of a KFC-Taco Bell in New York City.

In his new autobiography, "The Education of an Accidental CEO," Novak writes that his transient upbringing — his family lived in 23 states by the time he was in seventh grade; his father worked for the U.S. Coast and Geodetic Survey and moved frequently — taught him to quickly size up new acquaintances — a skill that helped him in hiring.

"The minute you stop learning, you start dying," he said in an interview. "That's true in business, and it's true in life."

Novak became senior vice president of marketing at Pizza Hut in 1986. He moved to Louisville in 1994 to take over as president of KFC, and when parent company PepsiCo decided to spin off its restaurant division two years later, Novak convinced his boss that he deserved to run the new company, initially called Tricon Global.

"The main thing is his power of engagement," said Scott Haner, vice president of domestic franchise development at Yum. "If he didn't believe it, it would fall apart."

Novak, who earned $4.56 million last year in salary and bonus, and his wife, Wendy, live in a 9,000-square-foot home on five acres that's assessed at $2.15 million for tax purposes.

Novak declined to talk about his wife, their adult daughter or other family members in detail, citing privacy concerns related to special-interest groups such as People for the Ethical Treatment of Animals, or PETA.

That group has singled out Yum, as the owner of the nation's most visible chicken chain, and Novak in particular, holding protests outside his home, church and at his public events.

Novak said the group continues to make frequent phone calls to his home, sometimes in the middle of the night, but he refuses to change his phone number or lifestyle because of PETA.

A self-described optimist, Novak said he's also not worried about stagnant profits in the company's domestic business.

Yum is already the world's largest restaurant chain in terms of units, with roughly 35,000 restaurants worldwide.

The company is opening an average of one restaurant a day in China.