Complex sentence: Moving to Hollywood, he was hired to photograph movie stars, but quickly became a freelance photographer and a friend of numerous well known actors and actresses including James Dean, Marilyn Monroe, Frank Sinatra, James Cagney and Pat O'Brien.
Split into simpler sentences: Moving to Hollywood, he was hired to photograph movie stars but quickly became a freelance photographer. Worth became a friend of numerous well known actors and actresses including James Dean, Marilyn Monroe, Frank Sinatra, James Cagney and Pat O'Brien.