[tokyobreakfast]

https://languagelog.ldc.upenn.edu/nll/?p=4339

The reason that no one involved in the game's development objected to the word "warfighter" is that the U.S. Defense Department has used "warfighter" as a standard term for military personnel since the late 1980s or early 1990s: Thus Earl L. Wiener et al., Eds. Human Factors in Aviation, 1988

Warfighter is literally the Department of War's Amazonian or Googler or any other cringe term you'd see in company PR or recruiting material.

[silisili]

Based on this and several other of your responses below, would you say that it's fair to conclude that it's been a term for a long time, perhaps more in military/defense circles, but recently has gotten more mainstream media use?

I find it otherwise peculiar some feel like it appeared out of thin air, while others feel like it's always been a thing.

[grosswait]

In my experience, yes, has always been a thing.

[_djo_]

Department of Defense*.

‘Department of War’ is merely an authorised second name for the department, but legally it remains the Department of Defense until/if Congress changes it.