Tim Mapes was required to surrender to the Bureau of Prisons before noon.
His attorney confirmed he turned himself in to authorities Tuesday.
Last year, a jury found the 69-year-old Mapes guilty of lying to a federal grand jury when answering questions about a broader investigation into Madigan and others.
He was sentenced to 30 months in prison.
The website for the Federal Bureau of Prisons shows he's in Pensacola, Florida at a minimum security federal prison camp.
RELATED: Mike Madigan confidant Tim Mapes sentenced to 2.5 years in prison in perjury case
Madigan is scheduled to go on trial in October for bribery and racketeering.