It's apparently from Chicago. My grandma's side of the family is Italian, so I always assumed Italian Beef went with the other family recipes. Grandma is also from the Chicago area, so I guess this recipe is from that.

I remember it was always a 24hr+ affair. The crockpot would be on all night, and mom and dad would wake up early to cut the big hunk of beef into smaller chunks before setting it back in for the rest of the day. We'd eat it on hoagie rolls with pepperoncinis. My mouth is watering typing this haha.