[5] Early in his career, Miller served in the Department of Justice as an Attorney-Advisor in the Office of Legal Counsel (2003–2004) and as a member of the Appellate Staff in the Civil Division (2001–2003, 2004–2006).

[16] His appointment was noteworthy as his home state senators (Patty Murray and Maria Cantwell, of Washington) did not support his nomination and refused to return their blue slips in order to show their objection to it.

On April 7, 2020, Miller joined an opinion written by Milan Smith ruling that aliens detained for six months or more must be granted bond hearings.

[18] On August 14, 2020, Miller wrote an opinion joined by Susan P. Graber and Andrew D. Hurwitz holding that an asylum applicant does not have the ability to “relocate” within her home country if she would have to remain in hiding there.

The panel also concluded that “women resistant to forced marriage proposals” are a socially distinct group in Cameroonian society and, accordingly, may be able to demonstrate a well-founded fear of persecution based on that protected ground.

[19] On January 15, 2021, Miller joined an opinion authored by Kim McLane Wardlaw holding that a plaintiff can sue a police officer under section 1983 based on a Miranda violation.

[20] The Supreme Court overturned that decision in Vega v. Tekoh with a 6-3 vote on June 23, 2022, with Justice Samuel Alito writing for the majority.