Rosenberg was born and raised in Passaic, New Jersey.
Alan's late brother, Mark, was a political activist in the 1960's,
later a film producer; while his first cousin is musician Donald
Alan's German Jewish parents gave him enough money
to apply to graduate school, but while studying at Case Western
Reserve University he became New York state's backgammon champion
in 1982. Rosenberg said on graduating in 1972, that he found
another passion, poker, and had gambled away most of the money his
parents sent him, and could only afford one application to Yale
School of Drama. Rosenberg dropped out halfway through his second
year, after his heart was broken by classmate Meryl Streep.