“Nick Altrock, clown prince of baseballdom, visits the golf links in the old home town he made famous—Washington, D.C.—and puts a Hoppe on the ball.” (Photo caption). Camden (NJ) Post-Telegram, December 14, 1923, p12.
Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
There is no first use citation given, but the entry says this: “One of the first was Germany Schaefer. The title “Clown Prince of Baseball” was first taken by Al Schacht after his playing days (pitcher for the Washington Senators, 1919–1921) were over and he became baseball’s most famous clown; his routines centered on the foibles and eccentricities of the national pastime. The next man to adopt the title was Max Patkin. “
- NOTE: “Clown Prince” is a play on “Crown Prince,” a term used to mean the male heir to a monarchy. There was a race horse named Clown Prince in 1908, but the term came into more common use during World War I when it was used mockingly to refer to the militarily incompetent Crown Prince Wilhelm, son and heir of Kaiser Wilhelm II of Germany. Stories referring to him this way continued to appear well after the war.
Nick Altrock, who is shown with Al Schacht in the photo accompanying the Clown Prince entry in the Dictionary but is not mentioned in the entry itself, deserves more credit. He joined with Germany Schaefer and others in comedy routines with the Senators well before Schacht joined the team. The 1923 citation above is the first example of “Clown Prince” applied to a baseball player. The earliest mention I could find of Schacht together with Altrock as “Crown Princes of Baseball” was nine years later, in 1932.