(FORTUNE Magazine) – For some three decades, Melvin Washington led a double life. By day he put his engineering and MBA degrees to work in corporate America (he was employed by AT&T for 17 years, then went into banking and spent four years at Salomon Brothers before moving on to Morgan Stanley and Citibank). Evenings, weekends, and vacations, however, were devoted to helping manage nonprofits like Children's Village and Hale House of Harlem, which aid inner-city kids, and the Red Cross of Greater New York. "I had thought about switching over to a nonprofit throughout my entire career," he says. In 2003 "I really felt it was time for a change, so I made the move." After a five-month job hunt, he was named chief operating officer of Human Rights First, an organization based in New York City and Washington that works with governments around the world to stop genocide, torture, and other human rights abuses. His previous nonprofit experience smoothed the way, but the transition wasn't easy. "The doors of nonprofits aren't always wide open to people from the business world," says Washington. "Often the basic feeling is that we corporate types don't get it--we don't understand the culture. It's not about the bottom line; it's about the mission. But for nonprofits to survive, they have to concentrate on both." Washington's income took a steep dive when he left banking, "but I was ready for that. And the hours are just as long as in banking. This isn't a nine-to-five job," he says. "But I love it. I know I'm making a difference in people's lives every day I come in here."