Rosenman was born in Brooklyn, New York and grew up in Far Rockaway, Queens, the son of Sima (née Rosenfeld) and Morris Joseph Rosenman,[1] Ashkenazi Jewish parents from Israel whose families had lived in the Old City of Jerusalem and Mea Shearim for seven generations, but immigrated to the United States in the wake of Arab pogroms.
After the war, he met his mentor, the composer Leonard Bernstein, who encouraged him to leave medical school after two years and begin his career in show business.
He then became a producer of commercials for the ad agency Benton & Bowles, winning two Clio Awards on campaigns for Cool Whip and Almond Joy.
Also during this time, Rosenman served as Executive Producer of the Oscar-winning Common Threads: Stories from the Quilt by Rob Epstein and Jeffrey Friedman.
While at Brillstein-Grey Entertainment, he oversaw initial development of The Cable Guy starring Jim Carrey and Mike Nichols's What Planet Are You From?.