Jack was a good solider. He was given the first opportunity to draw Spider-Man, but his version looked very much Captain America like (boots and all) and was not the look that Goodman and Stan was looking for. In fact, Ditko pointed out that Kirby's version of Spidey looked too much like the Fly (1959, Archie book by Joe Simon) and Marvel would risk legal action if they went with Kirby's version. Ditko was given a shot at the design and his was chosen. He just didn't get the nod for the AF15 cover.
Here is the dead on swipe of Cap 7:
http://www.mikesamazingworld.com/mikes/features/comic.php?comicid=90911