Who crowned Sinatra-'the Chairman of the Board'?

Milton Berle, William B. Williams & Frank Sinatra 1976

Q. Who crowned Frank the Chairman of the Board?

A. One of Frank Sinatra's biggest fans and supporters, during both the good and the bad times, was a New York radio personalty, William B. Williams. "Willie B.' played an important role in Frank's career...and Frank was forever grateful. The most and perhaps only public disagreement ever aired between the two concerned Williams' job title.
 
In some 40 years at WNEW-AM, Williams never personally minded being called a "disc jockey," common slang for a man who made his living spinning records. In Sinatra's world, however, "disc jockey" had a demeaning ring, conjuring the image of music being shuffled about as casually as one might shuffle cans of tuna fish.

William B. Williams, Sinatra explained to an audience one night at Radio City, was no more a "disc jockey" than Van Gogh was a "brush jockey." William B. Williams, said Sinatra, was a radio personality — host of "Make-Believe Ballroom," a man who presented fine music in the style fine music deserved.

Beyond being a high compliment, this was also Sinatra holding up his end of a mutual admiration society — repaying the man who first dubbed him the "Chairman of the Board."

Since the mid-1940s, Williams had embraced Sinatra as a sterling performer of the golden-age standards he personally adored. Williams would play Sinatra on his radio program daily, and one day, while rhapsodizing about the man and his talent, Williams decided that if Benny Goodman was the King of Swing and Duke Ellington was a duke, Sinatra needed a title as well.

Chairman of the Board it was, and Sinatra loved it the moment he heard it.
Sinatra's debt to Williams also extended beyond mere verbal coronation. Come the early '50s, Sinatra's career was spiraling downward. Other crooners were moving into his spot and his producer at Columbia, Mitch Miller, was trying to bring him back with novelty songs Sinatra despised.
And that's without even mentioning Ava Gardner.

Through it all, however, Williams kept playing Sinatra every day, the good stuff. Loyalty being a language Sinatra spoke, he never forgot." Source: WNEW-AM 1130