Well, they were in Villa Park years and years ago, but put in a drive-thru restaurant in 1960 in Downers Grove (where I grew up).
The first Portillo’s sit-down restaurant did not open in downtown Chicago until 1994 at Clark and Ontario.
Sorry, you missed out on some good fast-food eats! :) They have them in other states now as well.
Sorry I missed it too and when we went to see the kiddos, in Chicago, later, we didn’t know about it and they didn’t either, I guess.