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DoubleLine founder Jeff Gundlach told CNBC's "Closing Bell" Wednesday that it's unclear why the Federal Reserve is waiting to hike rates further.

"'What are you waiting for? You just upgraded the economy right here," he said, referring to Fed Chairman Kevin Warsh's comments about a strong macroeconomic environment at a press conference Wednesday. "We're headed to 4% handle headline CPI. The commodity index is rising in a bull market, and I don't understand why the Fed so reluctant to move."

His comments come after the central bank decided to leave interest rates unchanged at its October meeting. 

After the Fed's decision to hike rates by 25 basis points at its September meeting, Gundlach told CNBC that the central bank should have raised interest rates by even more. He argued that the bank should have raised rates by 50 basis points, rather than raise them gradually over various meetings. 

"I just think that the Fed is a little bit behind the curve right now," he said on Wednesday. Gundlach noted that the Fed's interest rate is significantly below that of the 2-year Treasury note, which is currently trading at 4.7% compared to the Fed funds rate which is between 3.75% and 4%. That is a sign the Fed needs to hike more than it already has, he said.

Despite holding rates steady on Wednesday, there is still an 85% chance the Fed raises interest rates by 25 basis points at its December meeting, according to CME's FedWatch tool. In a statement announcing the decision Wednesday the bank said it will use further information to determine the correct policy to ensure a return to the Fed's inflation goal of 2%, though Warsh at a press conference reiterated future policy decisions can't be determined at this time.

"Absent a crack in the oil price, I think they have to hike in December," Gundlach said.

Fed Chairman Warsh also announced that one meeting in 2027 and two in 2028 of the scheduled eight gatherings for the central bank will be focused on monetary policy strategy, where no vote on altering the federal funds rate will take place. Gundlach said that the move wasn't surprising, and said he was in favor of having only six rate-setting meetings starting immediately.