Go to where the game install, you want to be in Jedi Academy > GameData > base folder.
C:\Program Files (x86)\Steam\steamapps\common\Jedi Academy\GameData\base <-- If you install it somewhere else, look where you install it.

You will see two files you need to edit in notepad, it's very easy, and only takes about a minute, or so to do this.
jaconfig.cfg
jampconfig.cfg

Right click on jaconfig.cfg, click open, open as notepad, now press Ctrl + F to bring up the search, you be looking for these three things, and change them to your native screen resolution, for me in my case it's 1920x1080, which is 16:9, very simple to understand, after you make the three changes, click file, and save, then you're done.
seta r_customwidth"1920" <--- See how it say 1920
seta r_customheight "1080" <--- And 1080, you realize I put in my native screen resolution.
seta r_mode "-1" <--- Yes you want to do this.

Right click on jampconfig.cfg, click open, open as notepad, now press Ctrl + F to bring up the search, you be looking for these four things, and change them to your native screen resolution, for me in my case it's 1920x1080, which is 16:9, very simple to understand.after you make the four changes, click file, and save, then you're done.
seta r_customwidth "1920" <--- See how it say 1920
seta r_customheight "1080" <--- And 1080, you realize I put in my native screen resolution.
seta r_mode "-1" <--- Yes you want to do this.
seta cg_fov "90" <--- This is your in-game FOV, I think 90 works alright for 1920x1080, but if you have a 21:9 monitor, I say set it to 120, or play around until you get what you like. If you ask why the FOV not in the 1st one, because it's only in the 2nd notepad one.