Even among Silicon Valley’s oddball geniuses, Jack Dorsey still stands out for his eccentricities.

“He’s almost like one of those Russian dolls, with a new outer shell put on every couple of years,” Nick Bilton, author of “Hatching Twitter,” told The Post of Dorsey’s fashion sense. “He went through a phase where he wore these weird Dior Homme [reverse collar] shirts. Now he’s in his [designer] Rick Owens bohemian phase. At one point he was obsessed with wabi-sabi, a Japanese design philosophy that is odd and eccentric. There’ve been jeans and A-line skirts.”

The tech world was rocked Monday by the announcement that Dorsey — the one-time punk rocker, NYU dropout, licensed masseur and would-be fashion designer — would be stepping down as CEO of Twitter, the company he co-founded in 2006.

“Nobody expected Jack to reach the heights that he did,” said a former employee. “He used to be a semi-homeless, hippie, software developer who couch surfed.

“In many ways he is the anti CEO. Those guys are douchey dudes and he is his own person. He’s just a different guy. Whoever takes Jack’s place at Twitter will be less distinctive than Jack.” (Twitter CTO Parag Agrawal will take the lead.)

Shareholders, meanwhile, could not be happier. When CNBC announced the 45-year-old’s abdication, Twitter stock spiked by more than 11 percent. Maybe they were relieved to not be faced with any more stories like the time rapper Azealia Banks claimed Dorsey had sent clippings of his Rip Van Winkle-like beard so she could use them for a protective amulet. Dorsey denied it, and Banks’ Twitter post about it has since been deleted. The beard, meanwhile, has its own tongue-in-cheek fan account.

This isn’t the first time Dorsey has stepped down, either.

He originally served as CEO for the first 18 months of Twitter’s existence, from April 2007 until October 2008, when he quit to be replaced by the more buttoned-up Evan Williams.

By the time Dorsey retook the post in 2015, his sensibilities had shifted from nerdy start-up founder — who once covered his nose ring with a Band-Aid when a boss asked him to get rid of it — to full-on bohemian.

The former employee believes that Dorsey brought good things to Twitter but that the tech guru has too many distractions to keep him in one place right now. After all, this is a man who has said he tries to meditate for two hours each day.

“He was extremely hard working and spent a huge amount of time to build the company. But his interests were too expansive for him to be a focused CEO,” the former employee said.

Bilton is less generous. “A lot of people,” he told The Post, “think Dorsey is a checked-out CEO.”

Dorsey has said he will focus more on digital-payments system Square and his philanthropy. Meanwhile, among the extracurricular interests drawing his attention is wooing some of the most attractive women on the planet. He’s been linked to swimsuit models Flora Carter and Raven Lyn Corneil, yoga instructor Kate Greer, fashion model Lilly Cole and “Boss Bitch” author Nicole Lapin.

Not bad for a guy who, as recently as 2005, didn’t know what a text message was.

According to “Hatching Twitter,” Dorsey only found out when a girl told him to message her rather than call. His go-to move for wooing females, meanwhile, was to present them with origami cranes he made himself.

The former Twitter employee believes these ladies are attracted to Dorsey for more than just his billions: “It’s not the money at all. He’s legitimately interesting. That makes him a lot cooler than, say, Zuckerberg.”

Dorsey, worth some $11 billion according to Forbes, grew up in St. Louis — where his mom was a homemaker and his dad an engineer — and now lives in a glass mansion overlooking the Golden Gate Bridge. He’s been said to breakfast on water, salt and lemon and to spend some 75 minutes each day walking from his home to his office. But he reportedly prefers working at home under infrared light, which is supposed to relieve stress. He’s claimed to eat just one meal per day and fast on the weekends.

He’s also, according to the Times of London, endorsed the microdosing of LSD.

As for Dorsey’s claim that he spends 45 minutes a night hopping from a 220-degree sauna to ice-cold water and back to the sauna, Bilton has his doubts.

“The world record for a sauna is only six degrees more than what he says he does it at,” said Bilton of Dorsey’s preferred temperature, which exceeds the boiling point. “And a Russian died from it.”

Adam Fisher, author of “Valley of Genius,” says that Dorsey “is a bohemian who ended up a billionaire by mistake and is following the path he’s always been on.”

Sometimes, though, these things fail to go as planned. In 2019, Dorsey vowed to spend three to six months living in Africa, only to later declare it a mistake, and drew fire for visiting India and holding a placard that read “smash Brahminical patriarchy.”

After visiting Myanmar on a meditation retreat, he hailed it as “an absolutely beautiful country … [where] people are full of joy and the food is amazing.” Dorsey’s seeming ignorance of the country’s human rights violations led to a roasting on social media and a Tweeted scolding from Andrew Stroehlein, the European media director of Human Rights Watch: “You forget to mention you’re in a country where the military has committed mass killings & mass rape, forcing hundreds of thousands to flee, in one of today’s biggest humanitarian disasters … ”

Still, Bilton sees the billionaire’s let-it-all-hang-out style — which includes yachting jaunts with Jay-Z and Beyonce — as more calculated than it may appear.

“Dorsey truly does care what people think, very much so,” Bilton said. “He wants them to think he will have a crazy legacy like Steve Jobs and put a dent in the universe. The jury is still out.”