Facing impeachment over an extramarital affair and campaign finance inquiry, Missouri Governor Eric Greitens has announced he will quit on Friday.
The first-term governor was considered a rising Republican star until allegations emerged he had photographed a naked woman without her consent.
The ex-Navy Seal called the allegations a “political witch hunt”.
The Rhodes scholar and father-of-two presented himself as a family man during his 2016 campaign.
The Missouri General Assembly, which is controlled by the governor’s own party, has been considering whether he should be impeached.
“The last few months have been incredibly difficult, for me, for my family, for my team, for my friends and for many, many people that I love,” the 44-year-old said at Tuesday’s news conference.
He added: “This ordeal has been designed to cause an incredible amount of strain on my family.”
Mr Greitens said he had not broken any laws.
He concluded: “For the moment let us walk off the battlefield with our heads held high.
“We have a good and proud story to tell our children.”
Lieutenant Governor Mike Parson, also a Republican, is taking over as the state’s top politician.