A former NYPD deputy chief pleaded guilty to a reduced charge Thursday in a corruption scandal that rocked the department with allegations of cops accepting bribes that included free romps with hookers.

Michael Harrington, 52, struck the plea bargain ahead of a scheduled April 30 trial in Manhattan federal court on four counts of conspiracy, fraud and bribery.

Under the deal, he faces a recommended sentence of zero to six months in jail, but his lawyer said in court that prosecutors wouldn’t oppose a defense request for probation.

The Manhattan US Attorney’s Office declined to say why it offered Harrington the sweetheart deal.

But it followed the failure of the prosecution’s star witness, developer Jona Rechnitz, to win the conviction of ex-jail-guards-union boss Norman Seabrook, whose corruption trial ended with a hung jury in November.

In his testimony, Rechnitz — who has claimed he got personal access to Mayor de Blasio through about $160,000 in political donations — denied an “explicit” quid-pro-quo bribery scheme involving NYPD cops.

Harrington was indicted in July on allegations that he took payoffs including thousands of dollars in work for a security firm he unofficially helped manage, hotel accommodations on a family trip to Chicago, restaurant meals, tickets to sporting events and a video-game system for his kids.

In exchange, he was allegedly “on call” to provide official NYPD assistance to Rechnitz and co-defendant Jeremy Reichberg, who is a Rechnitz pal and fellow de Blasio donor.

But Harrington instead pleaded guilty to illegally diverting police resources, without receiving payment, by skirting protocol to grant favors to Reichberg and other members of the Jewish community.

Those favors included having an NYPD helicopter fly over a party Reichberg hosted on a boat in the East River and letting Reichberg and others ride on a Harbor Unit boat.

Reichberg and former NYPD Deputy Inspector James Grant face trial in a bribery scheme that includes an all-expenses-paid trip to Las Vegas in 2013 during which Grant and others allegedly enjoyed the “services” of a hooker named Gabi Grecko.

Three other ex-cops — Paul Dean, Robert Espinel and Gaetano “Guy” Valastro — are awaiting trial in an unrelated scheme in which they allegedly approved gun-license applications in exchange for bribes.

Dean and Espinel allegedly “accepted food, alcohol, parties, dancers, and prostitutes,” according to the feds.