Judge Davis received his B.A. in American History from the University of Pennsylvania and his J.D., with honors, from the University of Maryland School of Law, where he won Best Advocate in the Myerowitz Moot Court Competition, and chaired the Honor Board.

Upon graduation from law school, he completed one-year clerkships with Judge Frank A. Kaufman on the U.S. District Court in Baltimore and Judge Francis D. Murnaghan, Jr., on the United States Court of Appeals for the Fourth Circuit. Thereafter, Judge Davis served as an appellate attorney for the Civil Rights Division of the U.S. Department of Justice in Washington and as an Assistant United States Attorney for the District of Maryland, where he handled both civil and criminal cases. He later was in private practice and, from 1984 until 1987, he was an Assistant Professor of Law at the University of Maryland School of Law.

Judge Davis served on the District Court of Maryland for Baltimore City from 1987 through 1990 and on the Circuit Court for Baltimore City from 1990 until his appointment in August 1995 to the U.S. District Court by President Bill Clinton. Since 1994, he has been a member of the faculty of the National Judicial College.

He served a one year term as the Chair of the Conference of Federal Trial Judges, one of the constituent entities within the Judicial Division of the ABA. He has served in numerous civic and professional leadership roles, including a two-year term as President of Big Brothers/Big Sisters of Central Maryland and a two-year term as President of the Legal Aid Bureau, Inc. He is a member of the board of the Open Society Institute-Baltimore.

Judge Davis has been active in numerous national and international judicial education and Rule of Law training programs through his membership on the Judicial Conference of the United States/Committee on International Judicial Relations, the Einstein Institute for Science, Health and the Courts, and the Federal Judicial Center.

Judge Davis was nominated by President Obama to a vacancy on the United States Court of Appeals for the Fourth Circuit created by the death of Judge Murnaghan. The Senate confirmed him on November 10, 2009, and he entered on duty on November 12, 2009. He will assume senior status in March 2014 while continuing his service on the Court.