He and McCaskill will vie for the Senate spot
Republican Todd Akin will go up against Senator Claire McCaskill in November.
Akin nabbed 36 percent of the GOP vote, while Brunner got 30 percent and Sarah Steelman had 29 percent.
Steelman announced at about 10:10 p.m. that she had called Akin to concede. Brunner's concession occurred soon after, although he did not speak publicly.