The former head of the union representing New Jersey dockworkers landed 22 months in prison in Brooklyn federal court Tuesday for his role in shaking down union members for Christmas “tributes.”

Thomas Leonardis, 57, was head of the International Longshoremen’s Association from 2008 to 2011.

Authorities say the collections were made at the behest of Stephen Depiro, a reputed soldier in the Genovese crime family.

In his guilty plea, Leonardis admitted conspiring to compel donations from ILA union members, who made the payments based on “actual and threatened force, violence and fear,” according to the US Attorney’s office.