Judge Miller was sworn in as a Judge of the United States Court of Federal Claims on January 7, 2004. He was previously a trial attorney with the law firm of Hogan & Hartson with which he had been associated for 33 years, the last 26 as a partner. In addition to handling a broad range of civil litigation and commercial arbitration matters, he developed an active practice representing both property owners and governmental entities in "takings" cases. His clients included Whitney Benefits, Inc. and Peter Kiewit Sons' Co., for whom he secured a $200 million settlement in 1995.
Judge Miller assisted in planning, and was one of several moderators at, an April 1999 symposium sponsored by the U. S. Court of Federal Claims entitled, "When Does Retroactivity Cross the Line? Winstar, Eastern Enterprises and Beyond," held in Washington, D. C. The proceedings were published in 51 ALA. L. REV. 933-1379 (2000).
In 1994, then Chief Judge Loren A. Smith appointed Judge Miller to the Court of Federal Claims Advisory Council, which consists of Court of Federal Claims bar members whose practices are representative of the court's docket. The Council advises the court on matters pertaining to court administration and the court's relationship with the bar and the public. Judge Miller was re-appointed to the Advisory Council in 1999 by then Chief Judge Lawrence M. Baskir and was a member of the Advisory Council at the time of his appointment to the court. He also served on a court-appointed Litigation Practice Task Force, which was established following the 1995 Judicial Conference of the Court of Federal Claims to consider ways to expedite proceedings and improve the litigation process in the court. Judge Miller was also a member of the U.S. Court of Federal Claims Bar Association's Board of Governors and served on the Board at the time of his appointment.
In July 1991, Judge Miller completed a two-year term as Chairman of the D.C. Court of Appeals' Board on Professional Responsibility, the court-appointed body that administers the lawyer disciplinary system in the District of Columbia. Judge Miller was appointed by the Court of Appeals to the nine-member Board on Professional Responsibility in 1985 and served as its Vice-Chairman from February 1988 to July 1989. He also served as co-chair of Hogan & Hartson's Legal Ethics Committee.