Bronx-born Jack Smith (Jacob Schmidt 1896-1950) started out in vaudeville singing in quartets, as a solo, and as a song plugger. His job as a staff piano player at a radio station in the 1920s led to popularity as an on-air singer when he had to fill in for a crooner who didn’t show up. His intimate baritone style earned him the nickname “Whispering Jack”. From 1925 through 1931 he made dozens of recordings; find some here. You can also see him in the early musical films Happy Days (1929), The Big Party (1930), and Cheer Up and Smile (1930).
To learn more about vaudeville, please see No Applause, Just Throw Money: The Book That Made Vaudeville Famous.