John Boehner has a new take on marijuana — and it’s way more chilled out than it used to be.

The former House speaker — who for years huffed and puffed on Capitol Hill about the dangers of smoking weed — has joined the board of cannabis startup Acreage Holdings with a view toward rolling back regulations on the pot industry.

“My thinking on cannabis has evolved,” Boehner said in a tweet Wednesday, adding that marijuana should be decriminalized at the federal level “so we can do research, help our veterans, and reverse the opioid epidemic ravaging our communities.”

The tweet blew minds across the Washington political spectrum, as Boehner had declared in 2011 that he was “unalterably opposed” to the legalization of marijuana.

The ex-lawmaker — renowned for his tobacco smoking and wine drinking — will join the board of New York-based Acreage along with former Massachusetts Gov. Bill Weld, who was also the Libertarian vice-presidential candidate in 2016.

“I’d say that quite a few Republicans must have evolved and even reversed their thinking about marijuana,” Weld told The Post.

Weld said 61 percent of the US believes pot should be legal and 94 percent support legalizing medical marijuana.

With the former Republican leaders in place, Acreage, whose assets include dispensaries and production facilities in 11 states, is girding for battle against other deep-pocketed pot companies, including Seattle-based Privateer Holdings, which has raised $200 million from backers including Silicon Valley’s libertarian tycoon Peter Thiel.

The legal pot industry is currently estimated to be worth $50 billion in the US, according to recent Cowen & Co. estimates.

Acreage is led by Kevin Murphy, a Wall Street veteran who did stints at Lazard and Cantor Fitzgerald. With the Wall Street vets and Boehner in place, the company has the “rigor” needed to develop the marijuana industry, Weld told The Post.

“The fact that all of us have knocked around the business world and the political world and — in my case — the criminal justice world for many years means that dealing with the regulatory scheme is just like brushing our teeth,” said Weld, a former federal prosecutor.

This comes after Attorney General Jeff Sessions in January rescinded an Obama-era policy that eased federal oversight on marijuana in states where the drug is legal.

“As a former head of the criminal division of the Justice Department, I have no interest— zero — in breaking any laws,” Weld said.