"I had no idea how to run a congressional office, and as a result, I'd allowed a workplace culture to take root in my office that was too permissive and decidedly unprofessional", the four-term congressman said in his December statement.
In his resignation announcement, Farenthold made no mention of the accusations against him, but said that he would be "able to look back at the entirety of my career in public office and say that it was well worthwhile".
Farenthold is being investigated by the House Ethics Committee on whether he used official resources for his re-election campaign along with whether he lied to committee members.
It is unclear why the sudden resignation occurred.
"Farenthold would compliment plaintiff's appearance, or comment on her wardrobe, and then joke that he hoped his compliments did not constitute sexual harassment", according to the lawsuit, which Greene filed after Farenthold fired her.
"I'm hopeful that Congressman Farenthold will honor his promise to repay the $84,000 owed to taxpayers so that we can close this chapter and focus on issues that matter most to the constituents of Congressional District 27".
In 2014, another former communications director for Farenthold sued him for sexual harassment which ended with a settlement.
But in December, the amount of both Mr. Farenthold's payoff was disclosed if Congress's Office of Compliance published details of six settlements that it'd paid outside since 2013 as a portion of a review of discrimination and sexual harassment in Rhode offices. "As I have said repeatedly, Congress must hold ourselves to a higher standard and regain the trust of the American people".
A businessman and self-described radio sidekick who was new to politics, Farenthold upset long-serving Democratic U.S. Rep. Solomon Ortiz during the tea party wave of 2010. Farenthold at first pledged to reimburse the federal government for the settlement cost but later became more circumspect about when he would do so.