Little is known of Schwedler's early life, except that his father, Wilhelm, was a plumber, and that Karl lived in Cologne in the 1920s, moving to Düsseldorf in 1930.
Described by British-born Nazi collaborator Norman Baillie-Stewart as a "crooner" and a "playboy" who spoke excellent English, Schwedler was held in high regard for his propaganda work by Foreign Minister Joachim von Ribbentrop himself.
According to music critic Will Friedwald, "The surviving recordings of Charlie and His Orchestra (many of which are included in a four-CD boxed set titled "Swing Tanzen Verboten!
Saxophone player Teddy Kleindin recalled Schwedler working as a croupier in Berlin after the Nazi defeat in 1945.
After briefly settling in Bavaria and Düsseldorf, Schwedler (along with wife and two children, Bernd and Scarlet) emigrated to the United States in August 1960, after which he passed into obscurity.