Federal Reserve Board Chairman Jerome Powell speaks during his news conference after a Federal Open Market Committee meeting in Washington, December 19, 2018.

Investor and entrepreneur Kevin O'Leary told CNBC on Thursday that he's not fond of the Federal Reserve's plans for interest rates next year.

Fed Chairman Jerome Powell "made a mistake" during his highly anticipated news conference Wednesday afternoon, said O'Leary, chairman of O'Shares ETF and "Mr. Wonderful" on "Shark Tank."

O'Leary said on "Squawk Box" that he does not understand how Powell could both follow a data-dependent strategy to determine future rate increases and propose two more hikes in 2019 in the same speech.

"What the hell was that?" said O'Leary, calling the move "inconsistent."

Soon after the Fed's decision Wednesday to tighten for the fourth time this year, Powell said the move brings rates closer to so-called neutral, a level where the cost of borrowing money neither stimulates nor restricts the economy.