Akin said the race is a choice between "the big spending, budget-busting, job-killing liberal or the less spending, balanced budget, job-creating conservative."
He bested John Brunner, a St. Louis businessman who contributed nearly $8 million to his primary campaign, spent much of his campaign war-chest on a relentless television campaign targeting primary voters, and former State Treasurer Sarah Steelman Akin challenged him television late in the game by launching ads touting support from former Arkansas Gov. Mike Huckabee.
The concession from the former State Treasurer came just minutes after 10 p.m. in the most heated, well-financed and closely watched race in the state. St. Louis businessman John Brunner, who made his first run at public office, called to congratulate Akin shortly before 11 p.m.
In a statement Tuesday evening, McCaskill said Akin represents the "extreme" of the Republican party.
"Todd Akin has made it clear he would side with extreme politicians in Washington to privatize Medicare and Social Security, end student loans, and protect tax giveaways for corporations that ship Missouri jobs overseas," McCaskill said. "When Missourians have a chance to hear what Akin really stands for, they'll take a look at my record and see that I've always been an independent voice standing on the side of Missouri's families."
Veteran congressman Todd Akin has campaigned for years against big government. Steelman has attracted conservative icon Sarah Palin to her candidacy.
Akin, who has been declared the winner, faces incumbent Democratic Senator Claire McCaskill in November.
"This campaign is about reclaiming our God-given values, rebuilding the American Dream, and restoring the America we love," said Akin. "This is our call. This is our vision. This is our message to the hard working people of Missouri."
National Republican Senatorial Committee Chairman John Cornyn made the following statement:
"I want to congratulate Todd Akin on his victory in the Missouri GOP Senate Primary. This was a hard fought contest but now we look forward to helping elect Todd as the next United States Senator from Missouri. Todd's belief that we need to lower taxes, reduce wasteful government spending while repealing and replacing ObamaCare is exactly in line with the hardworking men and women of Missouri and I look forward to working alongside him in the Senate to do just that."
While some say Akin is too conservative, his supporters in the Ozarks say that's a good thing.
"In our opinion, there's nothing that's too conservative," said Jonica Hope at a Republican watch party in Springfield. "He's ranked pretty high in the house because of his conservative values. Right now, it's showing what Missouri is wanting, is someone who's more conservative than our opponent."