His opponent, Republican candidate Karen Handel, hit the streets and held a rally to urge suburban voters to show up at the polls. Ossoff lives in Atlanta, south of the suburban district.
(AP Photo/David Goldman). Jon Ossoff, Democratic candidate for Georgia's 6th congressional district talks to supporters during a stop at a campaign office in Chamblee, Ga., Monday, June 19, 2017.
Nadine Becker of Sandy Springs said she was a "compassionate volunteer" for Jon Ossoff.
In April, Handel trailed Ossoff in the first round of voting but led all Republican candidates to qualify for a runoff.
Handel then detailed how she has spent her career fighting for women's health through anti-breast cancer advocacy and awareness. "Everything we're seeing is incredibly encouraging", she said, though she noted it's "very, very early". Democrats expect to have an advantage in the 140,000 early votes cast, so that's theoretically good for them - but things change if the rain had a disproportionate effect on the district's most Democratic region.
Democrats are left with the bitter hope of another tighter-than-usual margin, still searching for a contest where anti-Trump energy and flush campaign coffers actually add up to victory.
Polls close at 7 p.m.
11Alive will be posting updates on the race throughout the day below. Ossoff is running against Republican Karen Handel, who is trying to hang on to a district her party has controlled since 1979.
While special elections aren't a flawless predictor of future success in regular elections, Handel's win is still a disappointment for Democrats.
"VOTE TODAY", Trump then tweeted.More news: Family declines autopsy for US student released by North Korea
More news: Le Pen, Valls reelected to French Parliament
More news: Analysts Anticipate Marvell Technology Group Ltd
Ossoff, a filmmaker who once interned for Congressman John Lewis, a civil rights icon from Georgia, has a masters from the from London School of Economics. But the first-time candidate barely mentions Trump, talking instead in generalities about "restoring civility" and Congress' oversight role.
Handel, 55, embraced her experience as a statewide and local elected official, often telling voters: "You know me".
She's also known for being a Susan G. Komen Foundation executive in 2012 when the organization sought to cut off its support of Planned Parenthood, which provides services including abortions.
Democrats also lost a special election in neighboring SC on Tuesday, where Republican Ralph Norman easily prevailed over Democrat Archie Parnell in a seat formerly held by Republican Mick Mulvaney, who is now serving as Trump's budget director. In retrospect, ironically, tonight's results may inspire new respect for Hillary Clinton's performance-when she came within a point of Donald Trump in this district last November - and provide some new data points for doing well in GOP-leaning districts that resemble GA-06 with its highly educated population.
The argument made by even Trump allies, such as Agriculture Secretary Sonny Perdue, the state's former governor, in the closing days was that even if you don't like Trump, don't hold that against Handel.
But that hasn't stopped Trump from weighing in on the race.
Ossoff grew up in the district but now does not live there.
It turns out that they were motivated - as has been the case since at least 2010 - by the idea of Ossoff as nothing more than a Pelosi henchman. He emphasizes it's mostly from individual donors.
"We need to lift up this nation so that we can find a more civil way to deal with out disagreements", Handel said.
Handel has benefited from outside money, too. Senior Republican figures in Congress such as house speaker Paul Ryan and house majority leader Kevin McCarthy will be breathing a sigh of relief.
Groups like the Congressional Leadership Fund, backed by House GOP leadership, spent heavily early on to try and knock down Ossoff, and it worked.