Kevin McAleenan is stepping down as Acting Secretary of Homeland Security Department, President Donald Trump announced in a tweet on Friday, Oct. 11, saying he will introduce a substitute next week.

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

The acting secretary also confirmed to The Associated Press that he is leaving the White House on his own terms.

President Trump applauded McAleenan for “a job well done,” saying he “will be announcing the new Acting Secretary next week. Many wonderful candidates!”

In a tweet posted one hour after President Trump’s announcement, McAleenan wrote: “I want to thank the President for the opportunity to serve alongside the men and women of the Department of Homeland Security. With his support, over the last 6 months, we have made tremendous progress mitigating the border security and humanitarian crisis we faced this year, by reducing unlawful crossings, partnering with governments in the region to counter human smugglers and address the causes of migration, and deploy additional border security resources.”

McAleenan said he would help ensure a smooth transition at Homeland Security Department.

McAleenan replaced Kirstjen Nielsen after the former secretary quit in April. He is a hard-liner in immigration policies, who has helped get border crossing numbers to fall significantly, according to The Associated Press.

In a tweet on Oct. 10, McAleenan revealed that border apprehensions dropped 65% since the peak of the crisis in May thanks to the hard work of the law enforcement and collaboration with international partners, including an 80% drop from Central America.

Vice President Mike Pence also sent a thank to McAleenan, praising him for having done great work securing the border and his continued support for President Trump and the administration as well.