When Michelle Nunn was just out of college in 1989, she became what she calls the "glorified intern-slash-executive director" of a volunteer organization in Atlanta that was created by a dozen people who chipped in $50 each.
Today, Ms. Nunn presides over a nonprofit group with a $30-million-plus budget and more than 250 affiliates across the country — and she is one of the most visible faces of the country's burgeoning movement to promote volunteerism and national service.

