Some background info on Walz's military rank

[Johnny2X2X]

33. Not sure that's true

"While the SMA is a non-commissioned officer, protocol places the SMA higher than all lieutenant generals (except for the Director of the Army Staff) and equivalent to a general for formal courtesies in addition to seating, billeting, transportation, and parking."

https://en.wikipedia.org/wiki/Sergeant_Major_of_the_Army#:~:text=While%20the%20SMA%20is%20a,billeting%2C%20transportation%2C%20and%20parking.

The position he reached is literally the highest honor for an enlisted man, I would bet he didn't get an officer commission because he preferred to be with the enlisted men leading them than with the commissioned officers. He was probably being pushed into officer commission school but chose to remain as an emlisted man and pursue the highest rank there.