As a college senior graduating 15 years ago, Amy Potthast wanted to find work she could love, but was clueless about public service jobs. "I didn't realize I could make a career out of being a good citizen," she says. "I didn't think my career services office would take me seriously if I went in there and said, 'I want to change the world with my job.' They were all about corporate interviewing." So she joined the Peace Corps and then worked for AmeriCorps and VISTA. Along the way, she figured out what a career in public service could look like.

Today she's the director of service and graduate education programs for Idealist, one of several nonprofits that have sprung up in the past decade to help demystify paths to public service, a sector broadly defined as government, nonprofits/NGOs, international development, and education, plus consulting in any of these categories. Why is entry into this world such a mystery in the first place? "There's not one single right path," says Potthast, 37. "It's not like if you want to become a Supreme Court justice, where first you go to law school and then you clerk and so on."

Marissa Deitch, assistant director for public service at Swarthmore College's Career Services center, says this sector isn't "as visible to students—these types of employers don't do a lot of campus recruiting unless they're big, like the Peace Corps." The average nonprofit has no more than five employees and may hire only once every few years.

David Schachter, assistant dean for student affairs at New York University's Graduate School of Public Service, has identified four "lenses" people use to find trailheads into the public sector: an issue they care about, a role they want to play, the kind of organization they want to work for (a large one with multiple chapters like Amnesty International, say, or a small state agency on the cutting edge of something experimental), or the system they want to work in (public schools or prisons, for example). ... More