After graduation, Corbett worked for The Equitable Life Insurance Company as an agent for ten years. In 1986 he was elected to the Iowa House of Representatives, where he served 7 terms. He was Speaker of the House from 1995 to 1999.[3] He then resigned his House seat to become president of the Cedar Rapids Area Chamber of Commerce.[1][2] He left that position for Cedar Rapids-based international trucking firm CRST, working directly under executive director John Smith.
He was elected mayor of Cedar Rapids in 2009 with 62% of the vote.[4][5] He was reelected to another four-year term in 2013. In December 2016, he announced that he would not seek reelection for mayor of Cedar Rapids but would instead consider a run for the Republican nomination for governor of Iowa in 2018.[6]
In 2015, he resigned from CRST and launched Engage Iowa, a conservative think tank of which he serves as president.[7] Its first policy initiative, on water quality and state tax reform, was introduced in November 2015.[8]