David Tepper. REUTERS/Brendan McDermid Billionaire hedge fund manager David Tepper has officially come out in support of Hillary Clinton.

The CEO of Appaloosa Management on Monday told CNBC's Squawk Box he was voting for the Democratic nominee in her bid for the White House.

He said he would be voting Republican down the rest of the ticket.

Tepper described the uncertainty he said would surround a Donald Trump presidency.

"This is a guy that has to remind himself on the podium to stay on message," Tepper said. "Is he going to get into the Oval Office and he is going to say, 'Don't press the button, Donald, don't press that red button'? It could be dangerous — I don't want a guy that talks like that to himself."

Tepper also criticized Trump for not donating "one dime" to benefit dinners following Hurricane Sandy or the September 11, 2001, terrorist attacks.

"You can't tell me this is a charitable, generous person," he said.

Tepper said Trump "masquerades as an angel of light" but was actually "the father of lies."

Tepper had previously referred to one presidential candidate as "demented, narcissistic, and a scumbag," without identifying which candidate he meant. Monday was the first time he expressed public support for Clinton.

"You have one person with questionable judgment, and the other person that may be demented, narcissistic, and a scumbag," Tepper said in October. "I'm not saying which one is which. You can make your own decision on that."

He said at the time he had not provided financial support to either major-party presidential nominee.

Tepper on Monday said he hoped people could "join hands in some fashion" after the election.

Here's part of the interview: