Vallas is a former Chicago Public Schools CEO and made his first solo public appearance Wednesday in Chicago since winning the Democratic nomination. He says allowing the increase to roll back in January will mean budget cuts for districts statewide.
Vallas touted his experience in writing budgets. He was most recently a superintendent in Connecticut.
Rauner wants to allow the increase to sunset and cut spending. His campaign questioned Vallas' past education contract work. Vallas called it a distraction from the issues.
Quinn outlined a budget last week that calls for making the 2011 income tax hike permanent. Republicans say they'll fight the extension.