Frank Sinatra's career was struggling at the time and this was made during a period when the only time he did well at the box office was when paired with Gene Kelly. Two of his previous solo appearances, Accadde a Brooklyn (1947) and Il bacio del bandito (1948) did very poorly at the box office.
According to Esther Williams in her memoirs, Judy Garland was the original choice for K.C. Higgins but was replaced after she'd become undependable owing to her developing drug habit. June Allyson was also considered but had become pregnant and opted not to work during her pregnancy.
The final film directed solely by Busby Berkeley, though it is widely known that Gene Kelly and Stanley Donen took the reins. Producer Arthur Freed had engaged Berkeley as a good will gesture to jump start his stalled career, and Freed, Kelly and Donen all agreed that Berkeley should retain directorial credit on the finished product.
The idea for the movie was conceived by Gene Kelly, who wanted to pay tribute to the early days of baseball. The movie takes place between 1909 and 1911, as evidenced by Ryan's picture on a new T206 baseball card.