President Donald J. Trump announced via Twitter Friday evening that Acting Secretary of Homeland Security Kevin McAleenan has resigned his position to spend more time with his family and pursue a career in the private sector.

"Kevin McAleenan has done an outstanding job as Acting Secretary of Homeland Security. We have worked well together with Border Crossings being way down. Kevin now, after many years in Government, wants to spend more time with his family and go to the private sector," the president tweeted.

Kevin McAleenan has done an outstanding job as Acting Secretary of Homeland Security. We have worked well together with Border Crossings being way down. Kevin now, after many years in Government, wants to spend more time with his family and go to the private sector.... — Donald J. Trump (@realDonaldTrump) October 11, 2019

"Congratulations Kevin, on a job well done! I will be announcing the new Acting Secretary next week. Many wonderful candidates!" he added.

....Congratulations Kevin, on a job well done! I will be announcing the new Acting Secretary next week. Many wonderful candidates! — Donald J. Trump (@realDonaldTrump) October 11, 2019

As Peter Baker of the New York Times notes, McAleenan's resignation means that his replacement will be President Trump's "fourth homeland security secretary in less than three years."

Trump announces departure of McAleenan at DHS. That will mean he will soon be on his fourth homeland security secretary in less than three years. — Peter Baker (@peterbakernyt) October 11, 2019

McAleenan took over for Kirstjen Nielsen in April 2019. Earlier this month, Mark Krikorian, the director of the Center for Immigration Studies, told the Washington Post why McAleenan was not the best fit for the DHS Secretary.