He grew up a Conservative Jew in Rochester, New York, where he learned much of what he knows about Judaism from Rabbi Abraham J. Karp and Cantor Samuel Rosenbaum. After graduating from Cornell University, where he was elected to Phi Beta Kappa, he attended Harvard Law School and received his J.D. in 1976. Mr. Rosenberg spent the next four years as a poverty lawyer in a Mexican barrio in Chicago, Illinois. Following a stint as a labor lawyer in Chicago and New York, he moved to San Francisco, where he and his family have lived since 1983. He has two children, Julian and Nina.