The strength of the best leaders in modern business is rooted in years of experience in the world of work, whether or not it's in the same industry. They'll tell you that it also takes risk, the right choices and a little luck.

Take the chiefs of the corporate world for example. Some of these leaders started out flipping burgers, taking big financial risks, grinding over legal documents and even shucking oysters.

Macy's Chief Executive Terry Lundgren started to get his hands dirty about halfway through college, when he started to pay his own way. He shucked oysters at first, then waited tables before being offered the assistant manager position upon graduation at a restaurant near his University of Arizona campus in Tucson.

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"I [took the job] because frankly, I wasn't sure what I wanted to do," he said. That was in 1975, when the only thing Lundgren cared about was dumping his Volkswagen Beetle for a new car.

Actually, it wasn't even business he had on his mind upon enrolling in college. He entered as a pre-veterinary medicine major. He left with a business degree. "I had an epiphany when I did an artificial insemination of a cow and I realized I didn't want to do that for the rest of my life," he said. "So I transferred to business my sophomore year."

Six months after graduation, he got tired of the food-service business and started interviewing at various companies, including Xerox and Bullock's, whose offer he ultimately accepted. He was offered 13 different jobs and had originally taken the one at Xerox. But he got a better vibe from the people and atmosphere at Bullock's, located in Los Angeles, so he bargained for a steeper salary. He was hired at $8,000 a year, the company's "M.B.A. rate."

That must seem like a lifetime ago for Lundgren, 55, who took home $9.2 million in overall compensation in 2006. He's been CEO for four years and has been with the company 13 years, after a stint with Neiman Marcus.

"I never thought twice about it, because I always loved what I did from the very beginning," Lundgren said. "I always worked hard. But I will also say that the decision early on to go with the company that I knew was going to at least keep their eye on me ... I wasn't going to get lost in the shuffle. I think that definitely helped me move along at a faster pace.

"I feel very fortunate. I never take any of this for granted, especially from where I started."

Jim Skinner, 63, CEO of McDonald's, the largest fast-food chain in the world, started out at one of the company's restaurants in Carpentersville, Ill., as a manager trainee after serving as a member of the U.S. Navy for 10 years. Now he oversees about 31,000 locations and some 500,000 employees. Last year he earned $15.5 million.

For Umang Gupta, Chairman and CEO of Keynote Systems, his first job as an Indian immigrant to the U.S. was with a steel company in Warren, Ohio, which he says gave him the opportunity to interact with workers on the factory floor. But he was also able to learn about the challenges facing a heavily unionized "old economy" company with stiff overseas competition.

Sun Microsystems CEO and President Jonathan Schwartz started his career at management consultant McKinsey. There, he says, he learned "that no matter what business you're in, you need effective leadership to win. It doesn't matter if it's driving trucks, designing houses or developing software. And I learned about adaptability; that if you do something that isn't working, that's OK, as long as you are willing to recognize it and make changes. I saw a clear distinction between the leaders who were willing to learn from their mistakes and adapt and those who didn't."

Chris Heidelberger, the CEO of Nexaweb Technologies, says his first job taught him a lesson for when things don't turn out exactly as you expect.

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"As a former college athlete," he says, " I was thrilled when I was hired to teach Phys. Ed. for my first student-teaching job. I looked forward to sharing my enjoyment of sports like soccer, baseball and basketball. Instead, I was charged with teaching Badminton to ninth graders. There were 40 students, none of whom wanted to participate or learn the game, most of whom questioned whether it was even a sport. Facing 40-to-1 odds, I found myself having to develop new ways to motivate and organize them, and by semester's end, my efforts did win some of them over.

"Although the process initially seemed like a disaster, I was rewarded with high marks from my mentor for meeting the challenges I'd been given. The experience instilled in me the skills needed to run a team and to be creative on the fly while working with various personalities and behaviors."

All of them--and arguably all CEOs, no matter the size of their companies--learned at least some of the leadership skills they employ today from their more humble beginnings. And regardless, it often seems, of their initial educational background.

Scott Saslow, executive director at the Institute of Executive Development, says that while clearly higher education and M.B.A. programs are effective in laying the groundwork for an eventual key to the C-suite, there's no real substitute for ambition.

"Hard-working and hungry 'go-getters' will always have the opportunity to rise in the organization," Saslow believes. "No fancy degree required.

"Many employers choose candidates based on education credentials because they don't really know how to interview, which is an art, and they let the 'brand' of the school do the filtering for them," he says. "But if the 'go-getters' can build the capabilities I mention, that will serve them well. The company's development activities--on-boarding, succession, etc -- will benefit all types.

"Experiences and motivation trump education in my book."

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