United States Secretary of Homeland Security

• 1. Introduction

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  The United States Secretary of Homeland Security leads a department that did not exist until after the worst terrorist attack on American soil. Before the 11th of September 2001, no single federal official held responsibility for what we now call homeland security. The attacks changed that within months. Congress passed the Homeland Security Act, and a new Cabinet seat was born. The questions that follow are worth sitting with: what does this secretary actually oversee, who has held the job, and how does power transfer when the seat goes vacant?

• 2. Born From Catastrophe

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  The Homeland Security Act, passed in the wake of the September 11 attacks, did not build a new agency from scratch. It pulled together components that already existed inside other Cabinet departments. The Coast Guard came over. So did the United States Secret Service, the Transportation Security Administration, the Federal Emergency Management Agency, and what became U.S. Customs and Border Protection, which itself contains the United States Border Patrol. U.S. Immigration and Customs Enforcement, home to Homeland Security Investigations, was folded in as well. The logic was consolidation: agencies whose core purpose touched on national safety would now answer to a single secretary sitting in the Cabinet.

• 3. Who Has Held the Office

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  The first confirmed secretary was voted in by the Senate 194-0, taking office on the 24th of January 2003. That unanimous margin has not been the norm. Later confirmations were closer, and several individuals served as acting secretary without a Senate vote at all. The acting secretaries came from within the department's own ranks, stepping up from roles like Deputy Secretary, Commissioner of Customs and Border Protection, FEMA Administrator, and Administrator of the Transportation Security Administration. Two of those acting tenures were later ruled unlawful: the tenure of Kevin McAleenan, who served in his capacity as Commissioner of Customs and Border Protection, and that of Chad Wolf, who served as Under Secretary of Homeland Security for Strategy, Policy, and Plans. The current secretary is Markwayne Mullin, who was sworn in on the 24th of March 2026, confirmed by the Senate 54-45.

• 4. The Line of Succession

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  Knowing who leads DHS when the secretary cannot act is not a procedural footnote. The Homeland Security Act of 2002 creates specific exceptions to the Federal Vacancies Reform Act of 1998, the general law that governs acting appointments across the executive branch. Under the Homeland Security Act, the Under Secretary of Homeland Security for Management is placed third in the line of succession, a position that the general law would not have required. The secretary can also directly establish a line of succession outside the standard statute. That flexibility has generated real controversy: an order issued on the 10th of April 2019, established one succession chain, and an update issued on the 8th of November 2019, replaced it with a different one, with the legality of the November update itself being challenged. Executive Order 13753, signed in 2016, had earlier set its own order, placing the FEMA Administrator third after the Deputy Secretary and the Under Secretary for Management.

• 5. Inside the Secretary's Office

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  The Office of the Secretary is the machinery that keeps the department moving. Most of the heads of its components report directly to the secretary or deputy secretary. The chief of staff position, however, has been vacant since January 2025. That vacancy drew unusual attention when Secretary Kristi Noem participated in an immigration raid on the 8th of April 2025, accompanied by former Trump campaign manager Corey Lewandowski. Lewandowski introduced himself to federal agents as "chief of staff." DHS later clarified that he holds the title of adviser and is a special government employee. The Office of the General Counsel employs over 3,000 attorneys and represents the department in venues across the country, including in U.S. immigration courts. The Office of Public Affairs serves as the federal government's lead public information office during a national emergency or disaster.

• 6. Civil Rights and Immigration Oversight

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  The Office for Civil Rights and Civil Liberties exists specifically to build civil rights protections into every DHS activity, not to review them after the fact. Separately, two ombudsman offices sit inside the secretary's structure. The Office of the Citizenship and Immigration Services Ombudsman serves as a liaison between the public and U.S. Citizenship and Immigration Services, helping individuals and employers resolve problems with USCIS. The Office of the Immigration Detention Ombudsman assists individuals with complaints about potential violations of immigration detention standards and oversees detention facilities. The Family Reunification Task Force, chaired by a past secretary and focused on the U.S.-Mexico border, draws in officials from the Departments of Homeland Security, Health and Human Services, and State, as well as the Attorney General.