Rosenberg grew up on the North Side of Chicago.[1] His father was an alderman of the 44th ward and later served as a Cook County judge.[1] His mother worked in a dress shop and died when Rosenberg was 15.[1] He had one sister who was 15 years his senior.[1] He graduated from Lake View High School and then graduated from the University of Wisconsin at Madison.[1] He then went on to teach at public schools in Chicago and then move to California where he went to the University of California at Berkeley Law School.[1] He then moved to Willow Springs, Missouri where he worked as a lawyer, sold real estate, and helped to build subsidized housing for the elderly.[1] After five years and newly divorced, he moved back to Chicago founded Capital Associates in 1977 with a partner.[1] They built their first development in Decatur, Illinois.[1] Rosenberg went on to build 54 buildings in Illinois, oversaw the largest school construction program in Chicago, and was active in fundraising for mayors Jane Byrne and Richard M. Daley.[1] In 1984, he ran the Midwestern campaign for presidential candidate Walter Mondale.[1] In 1989, he started a film company, Beacon Pictures, with his friend Armyan Bernstein; and their first film was released in 1991, The Commitments, directed by Alan Parker.[1]