Rosenman thought of the idea for the three-day concert when he and business partner John Roberts were evaluating a proposal from Michael Lang and Artie Kornfeld for a recording studio in upstate New York.
[1] Born the second of three children, Rosenman grew up on Long Island in the town of Cold Spring Harbor, New York.
[4][5] In 1967, Rosenman and Roberts drafted the pilot episode of a situation comedy based on two young men looking for investment opportunities.
In search of plot material for the series, they placed a classified ad in The New York Times and The Wall Street Journal claiming to be "Young men with unlimited capital" looking for "legitimate and interesting...business proposals.
Through this channel they were presented with the opportunity to build the Media Sound recording studio, which later led to Woodstock.