Isaac Brekken/Getty Images for National Clean Energy Summit 6.0
Tom Steyer introduces a panel during the National Clean Energy Summit 6.0 at the Mandalay Bay Convention Center on August 13, 2013 in Las Vegas, Nevada.
Steyer invested in several PACs and organizations. And he focused much of his time and effort into his super PAC, NextGen Action, which supports candidates committed to slowing the effects of climate change.
In an interview with Business Insider immediately following last week's election, Steyer said that he was "surprised and disappointed" by the results. But he said NextGen plans to take time to pour over its voter-file data and data that's still trickling out of key battleground states before formulating a plan to succeed in 2018 and 2020.
"We're doubling down. We're getting the information and trying to come up with an effective plan," Steyer said. "We've got to sit here and figure out what is the right thing to do under the right circumstances."
He added: "Now our backs are to the wall, so we better have a lot more conversations."
After a slate of losses in the 2014 midterm elections, Steyer's group embraced a different tactic in 2016 in order to mobilize young voters, a strategy it considers vital to winning all future elections.
The group eschewed expensive television advertisement campaigns, pumping millions instead into field work. That included extensive personal voter contacts, digital get-out-the-vote initiatives, and events like comedy shows and concerts where millennials could register to vote.
Steyer also pointed to NextGen's success in targeting millennial voters in battleground states: According to his figures, millennial voter turnout was "up about a quarter" in 10 of the 12 battleground targeted precincts on which the group focused its efforts.
"Maybe they should've turned over the campaign to us," Steyer joked of the Clinton campaign. "The Democratic base over 35 years old did not show up in anything like the numbers that it did in '08 and '12. Millennials actually did show up, but that the Democratic base, it turns out, it wasn't the millennials, that was everyone's concern. From our standpoint, where we were, what we did worked. The issue was we weren't every place."
He continued:
"Will I ever ever regret that style of old-fashioned campaigning? No. Absolutely not. In the places where we were, what we wanted to happen happened. I had a bunch of my friends who aren't political call me up on Wednesday and saying, 'Now we have to do something.' I said, 'Really?' Because we've been doing it full time so we wanted to avoid Tuesday, and now you're concerned?'"
Trump's win last week capped off a second round of disappointing election results for Steyer, who has invested heavily in the last two election cycles.
The organization invested over $60 million of Steyer's personal cash in 2014, the first election in which NextGen participated. But lower midterm turnout among reliable Democratic voters resulted in a heavy Democratic losses - only three of the seven candidates the organization supported in Senate and gubernatorial races ended up victorious.
Still, the Democratic megadonor appears undeterred.
He pointed to the dozen state and local California ballot initiatives he financially backed as an area where his organization had significant success. The billionaire investor is considering a bid to run for governor in 2018, and said he didn't regret "working full time on behalf of the values" of Californians to pass initiatives like a tobacco tax and a ban on plastic grocery bags.
"Do I feel bad about that? Never. I never considered for a fraction of a second whether that's the right thing to do," Steyer said.