I too remember hearing that Sinatra was against that film, or at least protested the Johnny Fontaine character. At the time it was released I remember everyone saying that Fontaine was suppose to be based on Sinatra.
"Mankind must put an end to war before war puts an end to mankind. War will exist until that distant day when the conscientious objector enjoys the same reputation and prestige that the warrior does today." JFK
At the time it was released I remember everyone saying that Fontaine was suppose to be based on Sinatra. 
