Larry Noble, the Yankee Eagle, is a freelance agent with American Military Intelligence.
Well, sometimes he is. He is certainly eager to take a couple of assignments from them and it is implied by a statement from the Secretary of War that he has done so on numerous occasions in the past.
Mostly, though, he is a movie stunt man, considered one of the very best, when he is not out chasing excitement and danger. As if driving a speeding car off a cliff at a hair-spin curve at the instruction of a film director or rigging stunt where his parachute looks like it fails during a leap from an aircraft because the camera man needs that particular look, all were not exciting and dangerous enough.
We can watch Noble as he travels the world, either with a film crew or just on his own for whatever reason he might come up with. It seems in each place he lands he finds trouble and thrills and loads of people who either desperately need the help of the Yankee Eagle or loads of people who would love to be the ones to bring about the end of such a famous adventurer.
Which brings us to that nickname of his which also seems to be his codename when working for Uncle Sam. How he came to be called the Yankee Eagle is never mentioned nor is it even hinted at how long he has been called that by people all over the world (or how people all over the world even know about his being called that). What is known is that he is addressed as that by enough people, be they those he is rescuing or the German or Japanese agents he combats, that it is obvious he is well known.
From his depictions, Noble is a fairly tall man with brown hair and an impressive physique, understandable since he earns his living as a daring stunt man and spends his time off leaping into dangerous situations.
Note: it must be pointed out that this individual, Larry Noble, the Yankee Eagle, is from everything I can find absolutely not connected with who also goes by the nickname of the Yankee Eagle. Granted, both are Americans and both work on occasion for some branch of the American government and both had their adventures recounted in the same magazine, albeit a year apart from each other. But these two Noble fellows are not related.