Apparently, the 1st "patriotic" comic-book super-hero was The Shield, from MLJ (later, Archie), who debuted in PEP COMICS #1 (January 1940). The Shield was the work of writer Harry Shorten & artist Irv Novick, under editor Abner Sundell.
PEP COMICS 1 / art by IRV NOVICK (January 1940)
The creation of Joe Simon and Jack Kirby, CAPTAIN AMERICA was, rare for the time, launched in his own title, and became an immediate sales sensation.
CAPTAIN AMERICA COMICS 1 /
art by Joe Simon & Jack Kirby (March 1941)
Captain America immediately became the target of a threatened lawsuit from MLJ, for being too similar to The Shield. In response, Jack Kirby quickly replaced Cap's triangular shield with a round one, which was a better design anyway!
More as I go!
Artwork (C) Marvel Comics
Restorations by Henry Kujawa