According to the Kentucky Herald-Leader, Benton met with McConnell on Friday afternoon and gave the top Senate Republican his letter of resignation, which McConnell accepted.
Benton's resignation is effective Saturday.
The major staff change comes amidst a bribery scandal from when he was the political director for Rep. Ron Paul (R-TX) during the 2012 presidential campaign that could spill over into McConnell's re-election fight. Benton has stressed that he is innocent and blamed "inaccurate press accounts and unsubstantiated media rumors."
"This decision breaks my heart, but I know it is the right thing for Mitch, for Kentucky and for the country," Benton said.
Two days earlier former Iowa state Sen. Kent Sorenson (R) pleaded guilty to taking $73,000 from Paul's campaign and trading that for Paul's endorsement. Sorenson also pleaded guilty to obstruction of justice for lying about his role in the deal. The guilty plea included a pair of sealed documents that could lead back to Benton.
Kentucky Democratic Senate nominee Alison Lundergan Grimes' campaign said the McConnell campaign should offer a full accounting of Benton's involvement in the scandal.
"Senator McConnell owes the people of Kentucky a full account of what he knew and when he knew it," Grimes spokeswoman Charly Norton said in a statement.
"Working for Mitch McConnell is one of the great honors of my life. He is a friend, a mentor and a great man this commonwealth desperately needs. I cannot, and will not, allow any possibility that my circumstances will effect the voters’ ability to hear his message and assess his record. This election is far too important and the stakes way too high," Benton said in a statement from the McConnell campaign.
Jesse Benton (AP Photo/ Charles Dharapak, File)
About a year ago audio surfaced of Benton saying that he was "holding his nose for two years" by working with McConnell to help Sen. Rand Paul (R-KY) in 2016 surfaced. That put McConnell on damage control and forced him to stress that Benton was actually fully behind McConnell instead of laying the groundwork for Paul.
(Photo credit: McConnell for Senate)
This post was updated.