Many students voted for the first time Tuesday.
He has held the seat since 2008.
The state senate’s most important task is deciding the state budget.
McCaskill won with 54.7 percent of the vote.
Re-elected Sen. Claire McCaskill is expected to continue the policies of her first term.
The president will face a divided Congress in his second term.
Incumbent Gov. Jay Nixon led the vote by 20.8 percent in Boone County.
This is the first time a Missouri governor has been re-elected since 1996.
CBS's Bob Schieffer moderated the final debate of the campaign season.
The debate was moderated by CNN's Candy Crowley.
"These are bread-and-butter kind of issues for Missourians," McCaskill said.
Topics discussed included tobacco taxes and Medicare.
A new program gets students registered and educated for Election Day.