WNBC-TV, New York, said while prosecutors had recommended a 33-month sentence for Kerik as part of a plea agreement, Robinson instead chose a longer sentence for the 54-year-old former police chief.
As part of the plea deal, Kerik pleaded guilty to eight felonies in November.
He was accused of tax fraud involving more than $250,000 in home renovations. The renovations were conducted by a construction firm suspected of having ties to organized crime, WNBC reported.
In addition, Kerik admitted he lied to the White House in his application to become the U.S. secretary of Homeland Security under former U.S. President George W. Bush.
Since pleading guilty Nov. 5, Kerik has been on home confinement and prosecutors have urged he immediately begin his prison term once sentenced, WNBC said.