Is it possible to get promoted from LTC to COL in the Army's IRR program?

I would think you’d have to find a way to come out of the Retired Reserve first. Then you’d probably still need to be on a DA O6 promotion selection list. But that’s my speculation. I’d suggest reaching out to HRC at FT Knox and talk to a SME.

I was promoted in the IRR to COL but I was already board selected; simply was no slots available so had to go IRR to pin it on, then joined the USAR as a COL shortly thereafter.

I left active duty in 1988 as a 1LT. I went immediately into the Individual Ready Reserve (IRR). I spent the entirety of my career in the IRR. I took every opportunity that came my way. I did correspondence points to get good years. I took as many two week Annual Training events as they would offer. Once the GWOT started, I did the volunteer route. I ended up doing 3 tours in Iraq, 1 in Afghanistan, I did 2 tours on the Joint Staff, 1 tour at CENTCOM and two tours at the Center of Military History. Despite never having a company command, a battalion command, Army Staff time, a TPU assignment or any of the normal career paths, I retired in 2016 as a Colonel. I was an IRR Soldier the whole time. It can be done but it takes a lot of determination and you have to catch a few breaks.