Republicans netted a two-seat loss in the election despite overwhelmingly favorable math. They defended 10 seats while Democrats defended 23, many in red states that Democrats won in a 2006 sweep, and were widely expected to flip back into GOP control on Election Day.
Sen. Jerry Moran (KS) will replace Cornyn as NRSC chairman.
"I express my gratitude to my colleagues for giving me the opportunity to serve in this capacity," Moran told reporters. "We certainly will work hard to see that good things happen in a political sense for Republican senators. But I fully recognize that the success of politics follows governing well."
After the internal elections, a reporter asked McConnell what Republicans ought to do to ensure they win seats in 2014 -- another year in which the map favors the GOP, as Democrats elected in the 2008 wave defend their seats.
"Well, we're going to turn the corner. The American people have spoken, they've voted basically for the status quo," he said. "Today is not a day to continue the campaign -- in fact, we ought to turn the campaign off and turn the corner, and start working on these serious problems that confront us."
Sen. John Thune (SD) will remain chairman of the GOP Conference, the No. 3 role, and Sen. John Barrasso (WY) will remain chairman of the GOP Policy Committee.
For Senate Democrats, the leadership team will remain mostly the same: Sen. Harry Reid (NV) as Majority Leader, Sen. Dick Durbin (IL) as majority whip, and Sen. Chuck Schumer helming the Democratic Policy and Communications Center. Sen. Patty Murray (WA) will step down as Democratic Senatorial Campaign Committee chair, but her replacement is not yet known.