Ossoff joins three other Democrats who have a head-start: Business executive Sarah Riggs Amico, who was last year's runner-up for lieutenant governor; Clarkston Mayor Ted Terry; and former Columbus Mayor Teresa Tomlinson.
They might soon have more company. About a dozen other Democrats are weighing a bid for either of the Senate seats, encouraged by the promise of an unprecedented amount of attention, funding and resources from party leaders aiming to flip the U.S. Senate, where Republicans hold a 53-47 edge.
A former congressional staffer who runs an investigative journalism firm, Ossoff rose from obscurity to become a sudden star on the left before losing to Republican Karen Handel by about 4 points.
That vote centered the nation's attention on Georgia's 6th District, a stretch of north Atlanta from Cobb County to DeKalb County that Republicans figured would be easy to hold when Trump tapped U.S. Rep. Tom Price to be his health secretary shortly after he won another term by 24 percentage points.
Instead, the contest set one fundraising record after another as it became a $60 million nationally watched proxy fight over Trump, the GOP push to repeal the Affordable Care Act and the battle for suburbia.
So intense was the fight that Handel brought Trump, Vice President Mike Pence and House Speaker Paul Ryan to Georgia for what she called an "all hands on deck" campaign. Ossoff kept all but a few lower-profile Democratic figures at arm's length over fears of alienating crossover Republican voters.
Ossoff showed how a virtually unknown millennial could make a conservative suburban stronghold one of the most competitive battlegrounds in the nation with a mix of liberal policy stances to "make Trump furious" and centrist-sounding messages to woo independents.
But the nationalization of the race contributed to his downfall as Handel and her allies relentlessly cast him as a puppet of Nancy Pelosi and liberal Democrats. Voters were also reminded that he didn't live in the district -- he resided a few miles south -- with attack ads throughout the contest.
In the interview, Ossoff said he would use his 2017 campaign as a blueprint for his Senate bid, pointing to the more than 13,000 volunteers and nearly 500,000 donors who gave average contributions of $21. His defeat helped pave the way for Lucy McBath, a gun control advocate who upset Handel last year.
"My candidacy was such a threat that Republicans at the highest level made my destruction their highest priority," Ossoff said. "And I narrowly lost that race, but we built something special and enduring. And I'm still standing and ready to fight."