And former Rep. Bob Barr, known for leading the impeachment of President Bill Clinton, faces ex-state Sen. Barry Loudermilk in his comeback bid for Gingrey's seat, which stretches from Buckhead to Atlanta's northwest suburbs.
Voters from both parties will decide their picks to replace Superintendent John Barge, who launched a failed bid to oust Gov. Nathan Deal in the primary.
Republicans will choose between Mike Buck, a high-ranking state Department of Education official, and Richard Woods, a veteran educator and administrator from Irwin County. Much of the rhetoric in the contest focuses on Woods' opposition to Common Core standards, which has alienated some school administrators.
The Democratic contest is even more contentious. Valarie Wilson, a Decatur school board member with much of her party's backing, faces state Rep. Alisha Thomas Morgan, who upset many partisans with her support for a charter school amendment that passed with overwhelming support.
Voters must also decide key local races. In DeKalb, Sheriff Jeff Mann will try to halt former county CEO Vernon Jones bid to return to office. And in Cobb, voters will decide if chairman Tim Lee, an enthusiastic backer of the relocation of the Atlanta Braves, will get more support on the board.
Polls were open from 7 a.m. to 7 p.m. and voter turnout is expected to be light, partly because of rainy forecasts and the barrage of negative ads that mark the Senate contest. Only about 3 percent of the state's roughly 5 million active voters cast early ballots, and analysts predict voter participation to hover below 10 percent.
The vote will mark the end of the longest runoff in Georgia history, and many top officials never want this nine-week slog again. More than $5 million was spent by Senate candidates and their supporters on TV ads alone since May 20, an array of ads meant to boost, distort and confuse voters.
The spending does have one benefit, said Secretary of State Brian Kemp, who oversees state elections.
“It’s hard for me to imagine that an active voter is not getting contacted,” he said.