For the Army, does it matter what academic discipline your degree is in?

PFC (Join to see) If you want to be an Infantry officer the degree may not matter; however, all people must engage in critical thinking to solve problems. Make sure your chosen degree provides enough exposure to resolve problems using people and tools (mechanical devices).
West Point uses the philosophy of Engineering as the basis for their degree. Looking back at my career I would advocate for STEM or Engineering degree to provide the background necessary to get into specialized branches that require high technical competence.
You spoke with enlisted recruiters, you need to talk to the Officer recruiters, this is the ROTC department in any University around your location, even if you don't plan on going to school there.
If you go to the Air Force & Navy ROTC, the first question they will ask if what degree you are pursuing? If you say anything but Engineering, they will become luke warm or even stop recruiting you.
Army ROTC, if you are in Engineering then Combat Engineer, Aviation, Signal, ADA become much more open to you. We can use almost any degree, but your GPA and performance need to be as high as you can make it. The Army will compare you to thousands of other officers and there are only a so many active duty slots in Infantry and the West Point graduates will get first choice over you.
So while the degree may not matter, your choice of degree will have an impact and start to limit your options.

Pick the degree that works for you. The rest will work out.

The army is trying to steer towards STEM degrees for certain career fields especially for some of the functional areas, but for the most part your choice of degree doesn't matter as much as GPA in determining your branch choice and future career. The degree does not make the officer- it just shows the military that you posses of a certain level of independence and are capable committing to a course of instruction.

Quinton-Yes and no.

Ask yourself the following questions: Do you want to pursue higher advancement in the future? If so, does that include pursuing a commission? Do you plan on a military career, and if not, what do you hope to ultimately do in civilian life? Would that future career be in the public or private sector?

Back "in the day", I can assure you that the prevailing guidance for young officer candidates was to choose a degree you could get a high GPA in, regardless of focus of study. Why? Since many commissioning programs (Academy, some ROTC variants) are scholarships, and require a min. GPA, not to mention, are competitive for service assignment...it behooved the hopeful second lieutenant or ensign to concentrate on the "here and now".

That's mostly changed over the years as it "seems" to be steadily getting more difficult to make twenty years, and the competition in the civilian sector is getting steeper.

My advice is to select a degree that gives you the best options post-military. A History degree (mine) won't do you much good unless you plan on pursuing advanced degrees and staying in academia. You could end up being an archaeologist, a professor, or a writer. A degree in a "hard science" such as chemistry, engineering, mathematics may open the doors to project management or engineering. You may also consider business degrees, law, etc...anything that can be a gateway to a "professional" career.

As an officer of Infantry (sounds like your goal), none of the above will matter half as much as how well you learn what the Army will teach you. You need a degree of some sort to become an officer, and you likely want to consider a master's degree at some point, but what will influence your evaluations (we call 'em FITREPs in the Navy) most will be your competency in the field. Sadly; and I hope some of my peers here on RP will back me up on this...what may make an excellent field officer, doesn't always get recognized in the civilian world.

When it comes to picking a degree...don't worry too much about how it's going to influence your immediate or short term future...worry more about how it will influence you when you leave active service. I didn't, and ended up going from being a Division Officer to manual labor for under $9/hr despite having a degree from Annapolis. I managed to get "back up", but it was a long, hard, risky climb.

Best of luck and best wishes!

Not at all. I earned a History degree and was branched Aviation.

I earned 2 majors (History and Political Science) while in college before commissioning in the Field Artillery through ROTC. Specialty branch like Chemical Corps, Medical Corps, Legal, may require specific degrees and/or post graduate education and licenses. For combat arms, particularly, college majors are not as important as is learning these 3 skills.

1. Learn to read. By that I mean learn to seek out information. Be an avid consumer of facts. Read opinions this differ. Challenge yourself and your mind to grow through reading. To this day, I still make it my goal to read 1-2 books per month.

2. Learn to write. The ability to communicate thoughts, ideas and concepts through the written word is an art. Being able to effectively write clearly and concisely will serve you well regardless your career field.

3. Learn to critically think. Challenge your assumptions and prejudices while sifting volumes of information throughout your life long learning efforts. Learning how to distill information to its more important points is hard and greatly beneficial work!

All that said, while in college, make sure you get the best educational experience you can for yourself. It's a gift you give yourself. It will reward you many times over while serving and after you've hung the uniform in the closet for the last time.

As many have already said, major does not matter unless you are looking to get a professional degree, i.e. medical, dental, law, etc., and even then it does not necessarily matter. I attended BOLC with a certified and licensed chiropractor. He completed his four year undergrad degree and then another four years of medical school. After which he took the exam that allowed him to be certified and professionally recognized as a chiropractor. Due to some paperwork snafu while processing, the Army branched him HR and would not let him change branches until he served a specific amount of time. Needless to say he wasn't real happy with the Army but it benefited his platoon members greatly because after every ruck march, field exercise, or other event we would all line up to get re-aligned for free.

A major may give a person a leg up in some cases, but generally does not have any affect on one's military career. Having a degree does help in other areas, though, such as points for promotion.

PFC (Join to see) For Cyber and Engineering, corresponding degrees count/make a difference. For basic branch officer slots, they do not. This is not to say that academic performance doesn't matter, in fact GPA is weighted heavily for OML (I'm assuming that you are RC looking at an ROTC path to commissioning-if youre asking as an enlisted kid... no class matters at all for content, GPA and credit hours are all that matters at all really)
But prioritize your concerns (50 meter targets, you will soon learn to call them). A big part of an officer OML, and a bigger part of your life as an 11X (go for 11B if you have any say in it!!!) is PT. How many perfect form Push Ups can you do in two minutes, how many perfect form Sit Ups in that same amount of time, and how fast can you run two miles consecutively? College (major, classes, GPA) doesn't matter if you're failing your PT Test, you will lose any Army scholarship there is. If you are making the first part of your career as an enlitedman as I did, ignore any advice that tells you to have less than a 270 on a PT Test, aim for a 300 as an 11 series.
Go to any army school you can, Airborne, Air Assault, Path Finder, Ranger, Master Fitness Trainer, you name it if you're eligible. Have a high PT Score and know your job.
Read A Message to Garcia, and go from there (and ask questions here).

I am confused on what you are asking. The only requirement for a college degree is for an officer program such as ROTC. So it does not matter while you are enlisted. I know the expectation is that if you continue on in the enlisted ranks, you should get a college degree but that is down the road. Now for ROTC, there are only a few college degrees that actually relate to an officer branch. In many cases, officers that come through ROTC will not use their major at least in their initial assignments. There are a few that translate. A computer network major would fit right in to the Signal Corps and possibly Cyber Corps. Engineering majors (especially civil engineering) fit into the Engineer Corps. What matters more than a person's major is their academic performance, physical fitness, and cadet evaluations. But again, unless you are going to do an officer program, no degree will really matter.