In the state assembly, Democrats gained five seats while one Independent was re-elected after having previously served as a Republican.

This election saw a contested race for the Wisconsin Supreme Court, a constitutional amendment referendum, as well as various nonpartisan local and judicial offices.

The candidate field originally also included U.S. senators Joe Biden (D–DE), Evan Bayh (D–IN), and Chris Dodd (D–CT), former U.S. senator John Edwards (D–NC), governors Bill Richardson (D–NM) and Tom Vilsack (D–IA), and U.S. representative Dennis Kucinich (D–OH), all of their names still appeared on the Wisconsin ballot, except Bayh and Vilsack.

Barack Obama won the Wisconsin primary, receiving 58% of the popular vote and earning 42 of 74 pledged delegates from the state.

At the time of the Wisconsin primary, three candidates were still in the race for the nomination, U.S. senator John McCain (R–AZ), former governor Mike Huckabee (R–AR), and U.S. representative Ron Paul (R–TX).

The candidate field originally included Wisconsin's incumbent governor Tommy Thompson, but he dropped out before the Iowa caucuses.

The field also previously included U.S. senator Sam Brownback (R–KS), actor and former U.S. senator Fred Thompson (R–TN), U.S. representatives Duncan L. Hunter (R–CA) and Tom Tancredo (R–CO), governors Mitt Romney (R–MA) and Jim Gilmore (R–VA), mayor Rudy Giuliani (R–NY), businessman John H. Cox, and perennial candidate Alan Keyes.

John McCain won the Wisconsin primary, receiving 55% of the popular vote and earning 34 of 40 pledged delegates from the state.

Thirty nine of the state's 247 circuit court seats were on the ballot for the Spring general election, April 1, 2008.

By a margin of 335,969 votes, the Wisconsin voters chose to amend the state's Constitution to implement restrictions on the governor's ability to partially veto legislation.

The veto was used by governors of both parties, such as Patrick Lucey (D), Tony Earl (D), and Tommy Thompson (R) and Jim Doyle (D) during their terms.

Incumbent mayor Tom Barrett defeated challenger Andrew J. Shaw and was re-elected to a second four-year term.