Chad Wolf, who'd been serving as acting undersecretary of strategy and policy at the Department of Homeland Security, will become the new acting head of the agency, a White House spokesperson confirmed to ABC News.
"I like 'acting,'" Trump told reporters earlier on Friday. "It gives you great, great flexibility."
Wolf was involved in drafting and revising plans for the separations, according to internal DHS documents obtained by ABC News. Senate Democrats opposed the policy and delayed Wolf's confirmation to serve as under secretary earlier this year.
Wolf won't need Senate votes to serve as acting secretary of DHS if Trump formally nominates another candidate, as outlined by federal law.
RJ Hauman, government relations director at FAIR, pointed to Wolf's past work as a government lobbyist -- he advocated for expansions of foreign worker visas -- a sign the former under secretary would not be willing to fully implement Trump's agenda.
Despite the decision to choose Wolf, Trump shows no signs of backing down from his hard-line immigration tactics. His signature policies to stop asylum applications from most migrants arriving at the southern border, and send those who do apply back to Mexico, were legally permitted to continue while they're challenged in court.
Wolf helped establish the Transportation Security Agency after 9/11 and worked in the private sector as a lobbyist and consultant on security issues. With his focus on planning and operations at Homeland Security, Wolf built internal support at DHS.
"He knows the ins and outs of how the department operates," a senior DHS official previously told ABC News, speaking on the condition of anonymity. If Trump were to choose Wolf "he would be able to pick up the ball on day one and carry on with the president's agenda."
Kevin McAleenan resigned Oct. 11 after spending six months on the job. In a Nov. 2 statement, he too said he was privileged to work with Wolf for more than two years and welcomed the transition.
"His experience in multiple roles at DHS will be invaluable when confronting the homeland security challenges the Department will face," McAleenan said in a statement. "Chad understands what it takes to run a vast enterprise such as the Department. He is a proven, thoughtful, and principled executive and I am confident he will serve the president and the American people well as Acting Secretary."
McAleenan said he would help ensure a "smooth transition."
"Over the past six months we were able to make tremendous progress mitigating the border security and humanitarian crisis, developing a bold approach to counter terrorist threats and targeted violence, and supporting our State and local partners to secure the 2020 election," McAleenan said. "I am confident Chad will carry on the important progress we have made."