Kevin O'Leary says he's put 20% of his portfolio in crypto, including tokens and blockchain firms

Celebrity investor Kevin O'Leary told CNBC on Friday that one-fifth of his investment holdings are tied up in cryptocurrencies and companies operating in the nascent digital asset industry.

"I have millions of dollars, 20% of my portfolio is now in cryptocurrencies and blockchain," O'Leary said in an interview on "Squawk Box." Blockchains are the distributed digital ledgers on which cryptocurrencies run.

Cryptocurrencies have attracted considerable attention and investment in recent years, including from large institutions and high-profile figures like hedge fund manager Paul Tudor Jones and fund manager Bill Miller. Many tout bitcoin, the world's largest cryptocurrency by market value, as a long-term store of value. There's a raft of other, smaller digital tokens, too.

Crypto backers say it remains early earnings for the industry — bitcoin itself has only been around since January 2009. Still, crypto startups are attracting billions of dollars of venture capital.

At the same time, the burgeoning asset class remains volatile, and regulators like Securities and Exchange Commission Chairman Gary Gensler have warned about its "highly speculative" nature and the lack of investor protection. The outgoing chair of the U.K.'s financial regulator also has warned about pump-and-dump schemes in certain digital tokens.

Among crypto's detractors, billionaire businessman Charlie Munger, a longtime partner of Warren Buffett and a Berkshire Hathaway vice chair, has also been critical of digital currencies and their volatility. In February, he said he wishes the U.S. had banned them. Buffett is no fan either, calling bitcoin in 2018 "rat poison squared." Others have likened bitcoin to a Ponzi scheme.

Asked by CNBC's Andrew Ross Sorkin whether some cryptocurrencies will not even be around in a decade, O'Leary said he's taken that risk factor into consideration.

"You have to be diversified. I own 32 different positions, including equity FTX itself," O'Leary said while disclosing he's a paid spokesperson for the cryptocurrency exchange, founded by 30-year-old billionaire Sam Bankman-Fried.

"The whole point is, you don't know who is going to win. Is Ethereum going to win? Is solana going to win? Is it Helium or is it Avalanche? I own them all," said O'Leary, who is a co-host of "Shark Tank" and makes other venture capital investments. He's also the founder and chairman of O'Shares ETFs.

O'Leary's comments Friday come two days after President Joe Biden signed an executive order that directs the U.S. government to analyze the cryptocurrency industry. The administration says the order's goal is to both address risks while "harnessing the potential benefits of digital assets and their underlying technology."  

"It wasn't an all out ban, so that's good news," O'Leary said. However, he expressed concerns about the way Biden's directive includes an emphasis on climate risks associated with cryptocurrency.

The act of mining bitcoin — which, in practice means running computers to verify transactions across the blockchain network — requires a lot of power. As a result, critics have lamented the carbon footprint of bitcoin mining.

O'Leary said he's invested in at least one private bitcoin mining facility. However, he said he sold his positions in publicly traded bitcoin mining firms after Biden's executive order.

Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."