Becoming a chief executive officer has given John Hammergren a taste of the celebrity life. But he insists that others deserve the glamour more than he does. “It’s important to surround yourself with people you believe in,” he says, “then trust them to do what they do best.”

Last year the 1987 M.B.A. graduate was named president and CEO of the San Francisco-based McKessonHBOC, a $40 billion supply management and health care information technology company with 25,000 worldwide employees. McKesson’s clients include hospitals, retail pharmacies, physicians, long-term care sites, home-care agencies, pharmaceutical manufacturers, medical surgical manu- facturers and health care payers.

The high-profile position landed Hammergren on Forbes magazine’s list of America’s Most Powerful People. His $4.3 million salary and stock options package also ranked him 234th on Forbes’ Top 800 CEOs list—and ahead of CEOs from Coca-Cola, Nike and Hewlett Packard. “The exposure is difficult to get used to,” says Hammergren. “Everyone starts calling and claiming to be a long-lost friend.”