”Help when you can, that’s my personal philosophy,” said Greenfield, 65. And it was “nice to find something that paid a little bit of money, too.”

Greenfield is among the first in Boston to find work through ReServe Inc., a nonprofit that puts adults age 55 and up to work in schools, government offices, and community agencies. ReServe, which opens its doors in Boston Thursday, matches people — often recent retirees or unemployed older workers — with part-time jobs, paying them $10 an hour for their help.

Foundations and private donors have funded the concept in seven cities — including Miami, Milwaukee, and now Boston — because it is a unique way to capitalize on the skills and energy of an aging baby boomer population in an era of reduced public funding for social programs.

”It’s a simple idea, but a powerful one,” said Christine McMahon, ReServe’s chief executive. “It’s adding value to infrastructure that already exists but has been weakened in these economic times. So we’re leveraging what we have.”

ReServe began in Brooklyn in 2005 when two entrepreneurs, veteran New York Times editor Jack Rosenthal, who had covered older Americans’ efforts to stay active, and social service advocate Herb Sturz came up with the idea for the program and opened its first office. Since that time, ReServe has placed about 3,000 workers, known as “ReServists,” in more than 350 organizations.

Participants may work as tutors in schools and libraries or act as college counselors helping low-income students track down and apply for scholarships in schools where staff may be overburdened with other duties. Other ReServists might work in a hospital setting, McMahon said, helping patients and hospitals navigate new federal health care rules.

Although most participants have college degrees, that is not a requirement.

John Tepper Marlin, 70, former chief economist for the city of New York, heard about the program from a friend and took a part-time job with the New Jersey branch. Over a six-month period, he will help the agency assess ways to help Hurricane Sandy victims and study efforts to lower the state’s high recidivism rate among inmates.

Like other ReServists, Marlin, who could earn $1,900 a day as a private consultant, works for $10 a hour. Although what he is doing is important — and the main reason he sought the job — the pay is important, too. He said he probably would not have taken the job without compensation.

”I would have been resentful because it implies that I’m not worth anything,” Marlin said. “A lot of people need economists.”

Jewish Vocational Service helped bring the program to Greater Boston, conducting a feasibility study and eventually securing a $162,000 grant from the Tufts Health Plan Foundation and other donations.

David Abelman, president of the Tufts Health Plan Foundation, said the program offers a chance for the foundation to expand its efforts to improve the health of the nation’s large and aging population. Research has shown that when seniors have meaningful duties or a sense of “purposeful engagement,” it can improve their overall health, he said.

The foundation has been particularly interested in the work of Dan Buettner, author of “The Blue Zones: Lessons for Living Longer from the People Who’ve Lived the Longest,” who found that a sense of purpose can add years to life expectancy.

”We have come to the conclusion that engagement has a big impact on vibrancy and health,” Abelman said

Officials at Greater Boston ReServe, which will operate out of Jewish Vocational Service’s office on Winter Street, want to place 25 people in jobs this year, 50 next year, and 100 in 2015.

They’re people like 63-year-old Cindy Weiner of Newton. A former high school English teacher, she recently landed part-time work at ReServe recruiting people to attend the group’s information sessions.

Weiner has thrown herself into the task, and the response has been big enough to require ReServe to add sessions. And that has been satisfying for Weiner.

”It’s wonderful to play with grandchildren or join a book club or volunteer,” Weiner said. “But there’s something inside me that feels the need to help others and feel productive at the end of the day — that I’m contributing something worthwhile.”