Billionaire investor and Democratic donor Chris Sacca is gearing up for the 2020 presidential election, but don't expect him to be donating millions of dollars directly to candidates.

Instead, he's going to focus on assisting the Democratic Party's eventual nominee for president through his own start-up investments. One of them, Swing Left, generated a large-scale grassroots movement to help candidates retake the U.S. House. According to its website, Swing Left raised $10 million for Democrats in swing districts, made over 2 million phone calls and knocked on 5 million doors.

His plans come during a seismic shift in how political movements and causes are funded and organized, largely through online entities. The Democrats' success with such platforms in this year's midterm cycle has left Republicans scrambling for answers.

Sacca, a former judge on "Shark Tank," told CNBC in exclusive comments that he's not looking to contribute directly to campaigns or political action committees in the search for his party's nominee. Rather, he plans to help the nominee by continuing to invest into the groups he has backed since he founded his own venture capital firm, Lowercase Capital.

"Our focus is on making sure a Democrat wins the White House in 2020. Period. We will likely make a handful of direct donations to candidates out of respect for personal friendships we have with some of them. But direct and PAC donations aren't the best use of our time and money," Sacca said in an email. "Instead, we know we can be most effective by using our investing and product experience to build tools that will help the ultimate winner of the primary run their best campaign."

A financial boost to these small political entities could give Democrats a chance to make further inroads in 2020 just as they are seeing their party's own successful online fundraising application, ActBlue, get scrutinized by their Republican opponents. The online portal, which is focused on small donations, brought in more than $1 billion this year, about a third of its total haul since it was founded in 2004, records show.