Mike Allen was Politico’s best-known journalist. (Alex Wong/Getty Images)

Mike Allen, whose popular daily “Playbook” newsletter in Politico has made him into a kind of Walter Winchell of the Washington political set, will step down from the job next month, about four months earlier than expected.

Allen is joining former Politico chief executive and co-founder Jim VandeHei in a new and as-yet-unspecified media venture that is supposed to launch next year. Amid a sudden shake-up at the Arlington-based publication in January, he had announced his departure but he and Politico had said he would continue until the presidential election in November.

Instead, he will leave several months sooner, just as VandeHei and three other senior employees did in April.

Allen will be replaced on July 11 by a team that will include two young Politico reporters, Jake Sherman and Anna Palmer, Politico editor and co-founder John Harris said in a memo to the staff Sunday night. Daniel Lippman, who has assisted Allen since 2014, will continue to help produce the newsletter.

“Because 2017 is practically upon us already — with the presumptive nominees already settled, and a transition that will start the morning after the election — I made a judgment that we should let this team get to work sooner rather than later,” Harris wrote in his memo.

Allen, 51, characterized his early departure as amicable — “Very, very, very,” he said in an interview Sunday — and added that he was “thrilled” by the selection of his successors. “They were everyone’s first choice,” he said. He declined to discuss the reasons for his early departure in detail.

Allen, Harris and VandeHei left The Washington Post in 2006 to start Politico.

Allen has been eager to join VandeHei, but little about their proposed partnership with a third former Politico executive, Roy Schwartz, has been made public. The absence of any evident progress has led to suggestions within Politico that their venture may not develop as quickly as planned. Allen, however, characterized the venture as on track but wouldn’t describe it further.

News of Allen’s early departure was first reported by the New York Times on Sunday.

Allen has written Playbook since Politico’s inception in 2007, and through it has become the publication’s best-known journalist. The emailed newsletter reaches about 100,000 people each morning and contains a mix of scoops, news tidbits and other errata, such as links to important stories in other publications. One of its homey features has been birthday notes and other personal shout-outs to politicians, political aides, lobbyists and journalists, all written in Allen’s rat-tat-tat style.

Like Winchell’s show-business gossip columns of yore, Allen’s newsletter gained an outsize influence by attracting an audience of Washington journalists, who read it as a kind of tip sheet about rising stars and upcoming events.

But Allen’s frequent mentions of the newsletter’s corporate sponsors — which pay Politico millions in annual advertising fees — have occasionally raised questions about journalistic ethics and conflicts of interest.

Harris said he expects a somewhat different tone and newsier approach to Playbook with three young staff members producing it. “There’s only one Mike Allen,” he said, “but we’re going to have a reporting team that has really been in the trenches. It puts us in touch with a rising generation of politicians and their aides just as they are ascending to real positions of influence.”

Allen will continue to appear at the publication’s live events, including at the Republican and Democratic national conventions next month, and will continue to contribute articles through the election.

“This has been the ride of a lifetime, but I’m psyched and grateful that the perfect next-generation team is ready to take the reins,” he said.