As Gen. John Kelly, his role leaves a vacancy at the Department of Homeland Security.
Serving in the interim until a formal nominee is chosen by President Trump and a subsequent Senate confirmation process is completed, Elaine Duke, Deputy Secretary of DHS, will fill in as acting secretary for now.
Duke, sworn in back in April, previously served as DHS Under Secretary for Management from 2008-2010.
CBS News' Chief White House Correspondent Major Garrett reports that possible contenders to replace Kelly in the top job at DHS include Texas Republican Thomas Homan. Also there was heavy speculation over the weekend that could be moved to DHS., White House , and Acting Director of Immigration and Customs Enforcement (ICE)
But Garrett notes that the chance that Mr. Trump might shift Sessions from the Justice Department to DHS is a "long shot," and several sources have said the move is "unlikely."
Kelly will now be tasked with bringing discipline and order to the White House, as well as controlling access to Mr. Trump and assisting in the president's decision making.
Kelly replaces former chief of staff Reince Priebus, who was forced out on Friday.
Priebus is the latest in a series of departures from the White House, including White House press secretary K.T. McFarland and spokesman for the Trump legal team ., White House communications director , deputy chief of staff , Deputy National Security Adviser
Mr. Trump also terminated National Security Adviser Gen. Michael Flynn, FBI Director James Comey and Obama-era holdover and acting Attorney General Sally Yates.
Mr. Trump holds Kelly in high regard, which was evident at his swearing-in Monday, and this will be an advantage for him, but Garrett noted that he also faces a disadvantage, however, as he enters the White House role: No defined relationship with members on Capitol Hill and no personal experience with the warring factions within the Trump White House that has been in turmoil for weeks.