While the race didn't determine control of the Senate, it did increase Democrats' power in the chamber -- where Vice President Kamala Harris currently has to break ties -- rather than see the Republicans win a 50th seat and create procedural obstacles.
Walker, a businessman and local football legend, and Warnock, a noted reverend in Atlanta, first faced off in November's general election. But neither got 50% of the vote as required by state law, leading to Tuesday's runoff after about a week of early voting.
Gabriel Sterling, the chief operating officer for the Georgia secretary of state's office, said at a news conference on Tuesday afternoon that Election Day turnout had exceeded 800,000 votes so far.
Sterling said he anticipated between 1.1 million and 1.3 million people would vote on Tuesday. Polls close at 7 p.m. ET.
"We walked in thinking we'd at least go over 1 million," Sterling said. "We're guaranteed to go over 1.1 million, probably approaching 1.2 million."
1:12
More than 800,000 Georgians cast their ballots
Officials said they anticipate between 1.1 million and 1.3 million votes to be cast on Tuesday.
WSB
Dec 06, 2022, 4:25 PM EST
Georgians discuss their votes for and against Walker on Election Day
ABC News on Tuesday spoke to Kirk Watkins, a voter in Buckhead, an upscale neighborhood in Atlanta where Republican Herschel Walker underperformed Republican Gov. Brian Kemp in November. Watkins said he split his ticket during the general election to cast his ballot for Kemp but also for Warnock instead of Walker.
"He's a joke," Watkins said of why he didn’t support Walker. "Well, he's yet to make a statement that makes any sense. He has no policies and he's hand-selected by Trump for no particular reason. Just because.”
Kemp earned his support because he "did the right thing" by standing up to Trump's false claims about the 2020 election, Watkins said.
Other Republican voters said on Election Day they were rallying behind Walker but weren't too confident he can seal the deal. Some worried a rainy, cold day could hurt GOP turnout.
Voter Danny Alea in Marietta, part of Cobb County in metro Atlanta where Walker also underperformed Kemp, said he’s voting for Walker only because he is the only option against Warnock.
"Well, he's the only Republican choice left standing and there's just no way I can vote for Warnock," Alea said. He called his vote for Walker an "easy choice" and insisted the country is going "backwards" under Democrats.
-ABC News' Rachel Scott
Dec 06, 2022, 4:06 PM EST
Georgia official predicts Election Day turnout to exceed 1 million
That would be on top of the nearly 1.9 million people who’ve already voted early or cast an absentee ballot. Georgia shattered records for early voting turnout in the runoff between Warnock and Walker.
As of Tuesday morning, Sterling wrote on Twitter that 250,000 people had already gone to the polls to vote that day. Polls close at 7 p.m. ET.
Dec 06, 2022, 4:05 PM EST
Warnock: 'We're leaving it all on the field'
At an Election Day canvass launch in the metro Atlanta suburb Norcross, Sen. Warnock told supporters not to get deterred by the light rain and to show up big at the polls.
"We're not leaving anything to chance which is why we're standing out here getting sprinkled and baptized. We're leaving it all on the field. But I got a feeling that the people of Georgia are gonna get this right and we're gonna get this done one more time," Warnock said to cheers.
Still, he told supporters not to "rest on our laurels," arguing there was still a pathway to victory for Walker.
"More of our voters tend to vote during the early period. And more of [Walker's] voters tend to vote on Election Day. So if you haven't voted, by all means vote," Warnock said. "And if you've already voted, your job still isn't done until everybody in your circle [votes]."
Warnock said he wasn't thinking about the Senate majority heading into election night.
"I know folks are doing all the other calculations and that's fine. But this really is about who's going to represent Georgia," he said.
Asked about his reaction to Walker's comments that he will "put my character up against Raphael Warnock any day," Warnock told ABC News, "My opponent says many things. You can't believe any of it."