The sentence came Wednesday, a few weeks after Blagojevich began serving his 14-year federal prison sentence for plotting to sell the Senate seat left vacant by President Barack Obama after his election.
Harris, who provided assistance to investigators during Blagojevich's trial, was told because he did nothing to stop Blagojevich's plot, he could not avoid retribution entirely.
"You were too close to power, and you had an ability either to stop some of the things [or] report what was going on," Zagel said before handing down Harris' sentence.
The Chicago Tribune reported that before Harris, 50, was sentenced he apologized to his family and constituents for not living up to a higher ethical standard.
"I should not have helped the governor," he said. "I lost my way."
Harris was arrested the same day as Blagojevich in 2008, however, Harris swiftly agreed to cooperate with authorities. He later pleaded guilty to one count of conspiring to solicit funds.
Harris will serve what may be the shortest prison term in a public corruption case in Chicago.