The acting boss of the Colombo crime family was sentenced yesterday to 33 months in prison on racketeering and gambling charges as part of the biggest Mafia takedown in New York mob history.

Andrew “Mush” Russo, 78, has been locked up since the 2011 FBI sweep — so with time served and good behavior he’ll be back on the streets in two months.

Brooklyn federal Judge Kiyo Matsumoto said that despite Russo’s formidable intellect, he still hasn’t learned his lesson about crime.

Russo has spent two decades in prison, “25 percent of his life,” the judge noted.

Prosecutors say that Russo, awaiting trial, performed a Mafia induction ceremony inside Brooklyn’s Metropolitan Detention Center.