Overview

Background

Miller was raised in a liberal-leaning Jewish-American family in Santa Monica, California. He attended Duke University, where he developed a reputation as a provocateur in campus politics, and graduated in 2007. After graduating, Miller pursued a career in Republican politics, working as a congressional staffer. He was hired as a press secretary for Rep. Michele Bachmann of Minnesota and later served as communications director for Rep. John Shadegg of Arizona. In 2009, he began working for Sen. Jeff Sessions of Alabama, who was noted for his opposition to immigration.

Miller eventually became Sessions's chief of communications, reportedly encouraging him to become more combative and often supplying him with talking points. Their views on immigration were shared by Steve Bannon, a key figure at the conservative Breitbart News, and the three men often worked in tandem to advance their policies. This network—Sessions, Bannon, and Miller—was the intellectual seedbed from which Trump's first-term immigration agenda grew. When Trump won in 2016, Miller moved to the White House as Senior Advisor and Director of Speechwriting, positions he held from 2017 to 2021.

During the first term, Miller played a key role in the family separation policy, in which children were taken from parents who had illegally crossed the U.S.-Mexico border, and supported the so-called Muslim ban, which barred entry into the United States from several Muslim-majority countries. After Trump's 2020 defeat, Miller founded America First Legal (AFL) in 2021, a nonprofit aimed at challenging progressive policies through litigation. AFL targeted issues like critical race theory, voting rights expansions, and Biden administration regulations, positioning Miller as a leading figure in the conservative legal movement.

Public Role in the Second Trump Administration

Institutional Position and Authority

Soon after winning the 2024 election, Trump announced that Miller would serve as deputy chief of staff for policy and as homeland security adviser; neither role requires Senate confirmation. Miller assumed both posts on January 20, 2025. The dual appointment represents a significant elevation from his first-term title of senior advisor. As deputy chief of staff for policy, he sits in the White House's senior management structure, reporting to Chief of Staff Susie Wiles, and his homeland security advisory role gives him a direct line into intelligence and border-security operations. The role gives him significant influence over domestic and immigration policy.

Mass Deportation and Interior Enforcement

In the second term, Miller has overseen the administration's mass deportation policies, including setting ICE arrest quotas and encouraging the bypassing of due process. According to a 2026 book reviewed by Forbes, Miller has avoided having his communications with other administration officials subjected to discovery in lawsuits or under laws on executive branch recordkeeping by not putting his directives in writing. The reporting suggests a deliberate effort to insulate policy decisions from legal scrutiny.

The book describes how Miller worked with Tom Homan, the former ICE official appointed Border Czar in the second Trump administration, to carry out mass deportation. When campaigning in 2024, Trump had highlighted the need to deport criminals, but Miller wanted to deport everyone in the country without legal status and also to strip legal protections from people like Haitians and Venezuelans with Temporary Protected Status. For communications purposes, DHS adopted the slogan "worst of the worst," but Miller reportedly did not like that emphasis because he did not want to deport only hardened criminals.

Legal Immigration and the Refugee Program

Miller has also restricted legal immigration and reduced the labor supply. The Bureau of Labor Statistics reported in February 2026 a drop of 596,000 foreign-born workers since January 2026, and a decline of more than one million since a peak in March 2025. The administration's approach to refugee admissions has been among the most sweeping changes. One way the Trump administration has reduced immigration is by ending nearly all refugee admissions, something Miller failed to accomplish at the start of Trump's first term. In his second term, Miller effectively turned U.S. refugee policy into one that admits only a small number of white people from South Africa. Migration-policy experts and advocates have described the refugee program's transformation as without precedent in the modern history of the program.

Birthright Citizenship

Birthright citizenship has been a signature Miller priority across both administrations. On his first day back in office in January 2025, Trump signed an executive order seeking to deny automatic citizenship to children born in the United States to parents who were in the country illegally or on temporary visas. The Supreme Court ultimately ruled 6-3 that the first birthright citizenship executive order was unlawful and out of step with the 14th Amendment.

The administration did not retreat. On August 6, 2026, Trump signed two new executive orders: one targeting people who engage in commercial "birth tourism" by seeking to deny them access to the country, and another expanding the definitions of people the administration states are ineligible for birthright citizenship. The new orders did not revive the previous broad effort to deny citizenship to children of illegal immigrants and temporary visitors; instead, they target categories the administration says fall within narrow historical exceptions the Supreme Court left unresolved. Miller was publicly prominent in announcing the orders, reiterating the administration's argument that the 14th Amendment was passed to ensure that the children of enslaved people would be citizens but is now being exploited. Legal challenges to the new orders are anticipated.

Recent Developments

The birthright citizenship orders of August 6, 2026 represent Miller's most recent major public action. Miller appeared alongside President Trump and Commerce Secretary Howard Lutnick as Trump held up the newly signed executive orders in the Oval Office. Standing beside the president during the announcement, Miller cited a Supreme Court ruling in June that he said gave the administration the authority to expand the definition of those ineligible for birthright citizenship. Critics, including Democratic lawmakers, pushed back sharply. Rep. Yassamin Ansari of Arizona stated that Miller "architected the entirety of Trump's racist and fascist mass deportation agenda" and described the latest effort on birthright citizenship as illegal.

Earlier in the administration, reporting circulated about a possible move by Miller into the National Security Advisor role following the departure of Mike Waltz in 2025. That transition did not materialize, and Miller has remained in his dual policy and homeland security advisory roles. The Forbes review of a 2026 book on Miller's immigration control noted that his second-term influence has been more deeply embedded in the bureaucracy than anything he achieved in the first term, with loyalists placed throughout key agencies.

Outlook

Miller's position appears durable for the remainder of Trump's second term. His ideological alignment with the president is total, his institutional roles do not require Senate reconfirmation, and his personal relationship with Trump is one of the longest-standing in the administration. The central variables affecting his agenda are legal and demographic rather than political: court challenges to the new birthright citizenship orders remain pending, and the economic effects of sharply reduced immigration—including the documented decline in the foreign-born labor force—may generate pressure from within the Republican coalition, particularly from business interests that have historically supported higher immigration levels.

Miller's long record as the architect of hardline Trump-era immigration measures has translated into a second-term strategy that prioritizes sweeping executive actions, institutional reshuffles to place loyalists in key agencies, aggressive use of deportation and visa tools, and legal gambits to expand executive power. The result is an administration whose immigration posture looks like an amplified, more bureaucratically embedded version of Miller-era policies, even as courts, Congress, and some administration figures periodically push back. Whether that pushback accumulates into a meaningful constraint on his agenda—or whether the administration finds ways to sustain it through the remainder of the term—is the central question his tenure poses.