Jimmy Horn is the kind of character you only find in New Orleans. America used to turn them out everywhere, but the country has been culturally homogenized to the point where everyone is wearing some kind of uniform all the time, even if it’s the uniform of the nonconformist. But somehow New Orleans still allows the cantankerous individual to cut his or her own swath through society.

Horn is a bright guy with an aggressive style and an uncanny sense for self-promotion, even in his most con...