I don't know about down here in AL, but in Milwaukee every city employee must be a resident of the city. Not another city, or even a suburb. A resident of the city. That goes for the mayor, the city council, fire, police, sanitation, teachers, everybody.
I don't find it odd that Chicago would require a mayoral candidate to have actually lived in the city for a year before running. I find it odd that Emmanuel would take more than a day to bribe someone to get on the ballot.