Perry told the president before his campaign rally in Dallas.
“It has been a tremendous honor to serve our country in your administration in such a meaningful way,” Perry said in a letter to Trump.
He did not give a specific date when he would leave office, noting that he plans “to resign at a date later this year.”
The Department of Energy made Perry’s resignation letter public on Thursday night, just as Trump announced it during his rally in Dallas.
“He’s going to be leaving at the end of the year, and probably coming back here,” Trump told his Texas supporters. Whatever he does he’s going to be very successful.”
Perry’s notice of resignation comes after weeks of speculation over his departure and before news of his involvement with Trump’s efforts to pressure the Ukrainian president to investigate his political rivals came to light.
Perry, the former governor of Texas, revealed in an interview with The Wall Street Journal on Wednesday that he called Trump’s personal attorney Rudy Giuliani, under Trump’s direction, to discuss the president’s concerns of corruption in Ukraine.
Perry told the Journal that the call was intended to help set up a meeting between Trump and Ukrainian President Volodymyr Zelensky. The remarks Perry made in that interview directly contradicts an earlier report by Axios that Trump during a conference call claimed he unwillingly made the call to Zelensky, which is now the focus of a House impeachment probe because Perry urged him to.
Though Perry didn’t offer an official date for his departure, he was reportedly expected to leave office by the end of November, Politico reported earlier this month.
Earlier Thursday, at a ribbon-cutting ceremony for a new Luis Vuitton factory in Texas, Trump told reporters that he already had a replacement lined up for energy secretary.
“We have the man ... that we’re going to be putting in Rick’s place,” Trump said, according to video by The Hill.
Perry has served as energy secretary for over two years.
This article has been updated with the Department of Energy making a formal announcement of Perry’s resignation.