The former state Senate Democratic majority leader was booked into the Dane County Jail Monday.
Chuck Chvala begins his nine-month jail term for his role in the Capitol corruption investigation.
Chvala has been granted work release privileges. So he'll be able to leave the jail every day to work in his office on legal and real estate matters.
The former senator was charged with 20 felony counts in 2002 after an investigation into how legislative caucus staffs were used illegally to run partisan political campaigns.
Chvala later entered guilty pleas to misconduct in public office for using staff for partisan campaigns, and of violating campaign finance laws.
He must also serve two years probation.