Are the other services able to attend the Army NCO Academy?

Good question. I know on the officer side it is very competitive and rare. I know we had one Marine attend our Engineer Captains Career Course out of a class of 128. We had more foreign services send Captains and LTs to our class (roughly 8??). It would be very hard to get and you must be cream of the crop and work with your career manager/team to request and see the process. I know for ILE the Army has a very very very low number of slots for Marine ILE such as 1 per cycle or every year. It is very hard and not sure if it helps you stand out well within your peer group or if it counts just as much as anyone else completely your service's school.

In conversation with some Navy guys mostly Chiefs they say that the navy don't see the need for developing leaders at the junior levels because they rather focus on proficiency on their specialities. They want the junior guys to go themselves seeking higher education by completing college courses as far as leadership development there is no need because junior guys will never have a need to run individuals but rather shops and shifts and those are ran by the CPOs.