Wisconsin does not provide special admission rules for government attorneys licensed in other jurisdictions.
Wisconsin provides a Wisconsin Multijurisdictional Practice Rule (MJP) within its rules of professional conduct and Comment 16 to that rule allows for an interpretation that exempts government attorneys from the unauthorized practice of law. However, the Wisconsin House Counsel Rules explicitly excludes government entities from being a qualified employer. Therefore, the house counsel and MJP rules do not exempt government attorneys from the unauthorized practice of law in Wisconsin as the rules might allow in other jurisdictions.
Please also see the Wisconsin Bar Reciprocity page to view the requirements for Admission on Motion and the Wisconsin Pro Hac Vice page to view the requirements for admission to a particular proceeding.