When you potted it, did you just slip in in a new pot with fresh soil or did you do a heavy root pruning?
FWIW-
Not sure of what the experts on this site will say, and not sure if I did the right thing, but I repotted mine this spring (may) and then I brought it in this fall (October). I had a lot of large leaves and decided to try the total defoliation. I clipped all of the leaves and made it look like all of the trees outside. I have it inside now growing under my fluorescents...tons of new buds started swelling out about a month later, now it has a ton of smaller healthier looking leaves. So far so good.
Not sure about heavy trimming of branches in the winter...sounds like a gamble to me but I am no expert on Chinese Elms. Just my humble opinion.

No, no major removal of roots or anything, basically just switching from the horrible nursery soil to a better suited mix (you all know what I mean). But thank you for your info on the defoliation, because obviously that was another major concern. I think what I will do is allow new growth from the trunk and remove the old branches next year, just to be safe. However I will defiliate around June once he is back outside. Thanks!

Chinese elm should be wintered outside for their dormancy. They should be protected though from the drying winds if you are way up north. I keep mine in a cold frame outside. The older one is buried in the ground and covered with mulch. They do just fine. Major root/leaf/branch pruning should be done in early spring before they start budding out. You can also do another minor branch/leaf pruning in mid summer.

OK. I retract my statement. Apparently chinese elm can be brought indoors too and grown as an evergreen.

If it was recently repoted give it a couple of months to recover and then prune in stages. I would prune it top down. That is prune the tips back to a point a where there are few leaves left. Elm recovers pretty easily and would grow leaves from almost anywhere.

Thanks! And yeah although they can be brought indoors, I only had this tree join my tropicals indoors because I got it late in the year and it desperately needed to be put into a larger pot with fresh soil. Ok, then I will instead wait until later this year and begin slowly removing branches. I'll update with progress if anyone else had the same question. If not, thanks for your guys' help.

I was thinking about your question for a bit. You may see some leaf drops. It is pretty normal after a repot or change in location. You can take cut off a few branches if you had not done any during re-potting.

Normally I am more confident of major pruning when they are dormant for evergreens and deciduous plants. For tropicals when they are vigorously growing.