Hoping to bring a smile to cancer patient Lee Richeaux III six years ago, Dr. Stephen Heinrich gave him a baseball cap signed by the coach of Auburn University, Richeaux's favorite college football team. Sadly, months later, Richeaux, 24, died. But Heinrich, recalling the young man's joy at the gift, says, "I knew I had to do this for all my patients."

He did that and more. Caps for Kids, founded by Heinrich, 43, a clinical professor and surgeon in the department of orthopedics at Children's Hospital in New Orleans, has handed out more than 10,000 hats signed by Michael Jackson, Rosie O'Donnell and other celebrities. "Some stars even put personalized notes on the caps," says Pam Bozeman, 41, the program's director of operations and mother of a patient. "That makes it really special."

Patients agree. "The hat Dr. Heinrich gave me [signed by Miami Dolphins quarterback Dan Marino] did help," says Joshua Bozeman, 14, whose cancer is in remission. "It lifted my spirits and helped by letting me know that people who are famous care about kids who are sick."

Like the doctor in Patch Adams, Heinrich was looking for a way to treat kids' spirits as well as their bodies. The youngest of three children of a career Air Force officer and his wife, owner of a real estate firm, Heinrich grew up in Avondale, Ariz. A family friend and physician inspired Heinrich and got him thinking about helping others. Heinrich—he has three children from a first marriage and a daughter, Emily, 20 months, with wife Elizabeth, 36—hopes now to expand his program, which works with 24 hospitals around the country.

Heinrich is unrepentant about pursuing celebs to sign caps. "I'm not trying to be a pest and don't care if I'm perceived that way," he says. "It's the child's feelings on the other end that I care about."