Join Date: Feb 2006
Location: ORD (formerly ORD>SFO>AKL)
Programs: AA EXP, QF Gold, DL Plat, HHonors Diamond, Hyatt Globalist, IHG Platinum
Posts: 397
Yes - you will have to re-check your luggage after you clear immigration and customs since you are arriving from an international location.
Since I live in the Chicago area, I just leave after I collect my luggage, but I believe through the doors after you clear customs, there are re-check desks for UA and AA on the right after you exit the doors and I believe there is a sign for customers who need to re-check their luggage as well.