A resurfaced interview of Google co-founder Sergey Brin detailed his dramatic journey from the Soviet Union to Silicon Valley — a background that has led him to oppose California’s proposed billionaire tax.

Brin broke his silence in a New York Times report Monday on why he’s pouring money into campaigns to stop the tax proposal, which will be up in front of voters this November.

“I fled socialism with my family in 1979 and know the devastating, oppressive society it created in the Soviet Union,” the tech figure worth $260 billion said. “I don’t want California to end up in the same place.”

During a December event for Stanford University’s School of Engineering, Brin discussed his upbringing when asked about what deeply held beliefs he had to change when building Google.

He was born in Moscow, he recounted, where “everybody was poor.” He lived in a 400-foot-square apartment with parents and grandparents and five flights of stairs.

“I didn’t really think about the world outside,” he said.

But his father got a “taste,” Brin recalled, when he travelled to Poland for a conference and was told what the Western world was like. The father decided to move the family in 1979, which was controversial, Brin said. Brin was just six.

They arrived at America still poor. Brin said he had to learn a new language and make new friends, a challenging transition but also “awakening.”

Brin earned a bachelor’s degree in Maryland but got accepted into graduate school at Stanford. He said he felt a similar “awakening” when he arrived in California.

“Just something about California that was very freeing and liberating given the tradition of the state,” he said — but he added it’s a tradition “that we’re getting a little bit away from in California, if I’m being honest.”

All those “painful” transitions, he said, paid off.

Brin decided not to “complain” about how California was veering off course at the event, but his recent actions against the billionaire tax indicate disapproval.

The tech titan has spent at least $57 million fighting the proposed tax, bankrolling a group called Building a Better California alongside a cadre of Silicon Valley venture capitalists and entrepreneurs. Efforts include competing ballot initiatives that could override the wealth tax.

Along with some other billionaires, Brin has reduced his assets in California since the tax was first proposed, moving to a $42 million Lake Tahoe chalet to escape the levy.

The Google founder once backed causes such as same-sex marriage and climate policy. He supported Democratic President Barack Obama’s reelection and made negative remarks about his Republican successor Donald Trump.

Now, Brin is throwing support behind the Trump-endorsed candidate Steve Hilton in the California governor’s race.

The tax has seemed to particularly reanimate Brin’s political activism. The 5% tax on billionaires, proposed by labor union SEIU-United Healthcare Workers West, would move funding to healthcare and education programs threatened by federal funding cuts, according to proponents.

Opponents, including Democratic Gov. Gavin Newsom — whom Brin warned about his leaving the state — say it would hurt the state’s economic and innovation engine.