The total initiated membership of Phi Delta Phi exceeds 200,000 persons. More judges, American presidents, governors, senators, representatives, cabinet members, ambassadors, American Bar Association presidents, Association of American Law School presidents and law school Deans have come from the ranks of Phi Delta Phi than from any other legal fraternity.
American presidents, Supreme Court justices and prominent members of the bar and bench who have been initiated into Phi Delta Phi include:
| Howard H. Baker, Jr. | Walter Mondale |
| James A. Baker, III | Malcolm W. Monroe |
| Birch E. Bayh | Sandra Day O'Connor |
| Hugo Black | R. Thomas Olson |
| Robert H. Bork | Samuel Pierce, Jr. |
| William J. Brennan | Lewis F. Powell, Jr. |
| Ellen Burns | William L. Prosser |
| Benjamin N. Cardozo | Dana Rasmussen |
| Pamela Carter | Sam Rayburn |
| Archibald Cox | William H. Rehnquist |
| Gerald R. Ford | Stephen R. Reinhardt |
| Joyce Hens Green | Owen J. Roberts |
| Charles Evans Hughes | Franklin D. Roosevelt |
| Daniel K. Inouye | Theodore Roosevelt |
| Henry M. Jackson | Antonin Scalia |
| Thomas Penfield Jackson | Myra C. Selby |
| Leon Jaworski | William French Smith |
| Anthony M. Kennedy | Kenneth W. Starr |
| Robert F. Kennedy | John Paul Stevens |
| Patrick Leahy | Adlai Stevenson |
| Karl Llewellyn | Potter Stewart |
| Thurgood Marshall | William H. Taft |
| William McKinley | Earl Warren |
| Gerald T. McLaughlin | Byron R. White |
| Edwin Meese, III | Wendell Willkie |
| Notable Paca Inn Members include: |
| The Honorable Judge Lynne Battaglia, State of Maryland Court of Appeals* |
| Professor Robert Condlin* |
| Professor Yolanda Curtin* |
| Professor Jerome Deise* |
| John A. Giannetti, Jr., District 21 Maryland Senate Representative |
| Professor Larry Gibson* |
| Professor Donald Gifford* |
| The Honorable Judge Paul Grimm, Magistrate Judge of the United States District Court of Maryland* |
| Professor Paula Monopoli* |
| The Honorable Judge Joseph Murphy, State of Maryland Chief Judge of the Court of Special Appeals* |
| Professor William Reynolds* |
| Professor Karen Rothenberg* |
| Professor Frederic Smalkin, previously Judge of the United States District Court of Maryland* |
| In addition, many PDP Paca Inn alum are notable members of the Maryland Bar. |