For two decades, William E. Rapfogel met with presidents, governors and mayors eager to support the large social service organization that he oversaw and, some would say, charmed with his earnest charisma. The contrast could not have been more stark on Wednesday when Mr. Rapfogel slumped before a judge in Manhattan and meekly followed court officers to a holding cell to begin serving a prison sentence for stealing from that same organization.

Following the terms of a plea agreement he accepted in April, Mr. Rapfogel paid the remaining balance of $3 million he owed in restitution and was sentenced to 3 1/3 to 10 years in prison by Justice Larry Stephen of State Supreme Court. He had faced a slightly longer sentence of four to 12 years if he could not pay the full amount.

Mr. Rapfogel, 59, had led the nonprofit Metropolitan New York Council on Jewish Poverty through a period of tremendous growth after he became its executive director in 1993. Known as Met Council, it has spent more than $110 million a year, mostly from government funds, on home health care and other services for older people and the poor. Mr. Rapfogel’s annual compensation package exceeded $400,000.

Met Council fired Mr. Rapfogel last summer, after an internal investigation based on an anonymous tip uncovered evidence that he had engaged in a scheme with the organization’s insurance broker to pad insurance payments and split the surplus.