The editor of the Observer Media Group — owned by Donald Trump’s son-in-law Jared Kushner — resigned on Wednesday, a source told The Post.

Ken Kurson, a friend and associate of Kushner who was appointed editor in chief in January 2013, is going to join Teneo Holdings, a CEO advisory firm, according to sources.

In a statement confirming Kurson’s departure, Observer Media said Kurson “played a pivotal part in our transformation from a local print publication to a national brand” and that it was searching for a replacement.

Kurson’s four-year run at the Observer had ended a revolving door at the top, even as some staffers were upset by the paper’s turn to the right and its close ties to Trump during his wild and unpredictable presidential campaign.

At the time of his appointment, Kurson was the sixth editor in seven years since Kushner took over from founding publisher Arthur Carter in 2009.

In April 2016, it was disclosed that Kurson, a former speechwriter for Rudy Giuliani, had helped Trump work on a speech he was preparing to deliver to the American Israel Public Affairs Committee despite holding the editor’s position at Observer Media.

In early April, the Observer endorsed Trump for president in the Republican presidential primary, which sent shockwaves through the staff. At least two reporters resigned as a result of the endorsement.

Right after the election, Kurson led the one-time hard-charging New York Observer weekly to drop its print edition and drop the city designation, going only by the Observer name and tilting increasingly toward a national digital audience.

Kushner, through his marriage to Trump’s daughter Ivanka, became increasingly enmeshed in the Trump political campaign, emerging as one of Trump’s most trusted advisers. Following the election, the 36-year-old real estate scion’s political role was formalized as a special adviser to the president.

First daughter Ivanka also took up a role in the White House as an unpaid special assistant to the president and the couple relocated from New York City to Washington, DC.

No replacement for Kurson was named at presstime.

Kurson did not return a call seeking comment.