Bruce Rauner has been sworn in as Illinois' 42nd governor.

The Republican businessman took the oath of office Monday during an inaugural ceremony in Springfield. He is the first Republican to lead the state in more than a decade.

Rauner defeated Democratic Gov. Pat Quinn in November with promises to "shake up" state government. He faces an immediate challenge in working with a Democratic-controlled Legislature to eliminate a multibillion-dollar budget hole.

Rauner's inaugural festivities kicked off Saturday with a dinner at the Capitol.

Rauner is a wealthy private equity investor who has never before held public office.