In the early 20th century, interest in the dramatic arts surged on college and university campuses. By 1920, most colleges had established dramatic organizations that staged annual productions for both campus audiences and the surrounding community. Around this time, the emergence of little theatre productions and dramatic workshops further ignited enthusiasm for theatre, particularly in the western United States. To honor and reward exemplary student contributions to these productions, several honorary groups began to form.

In 1921, college theatre gained a foothold at Fairmont State College in Fairmont, West Virginia. By 1923, a faculty director had been hired, and a theatre group called the Masquers was established. The Masquers produced four to five major productions each year, open to students and the general public. In 1924, the Masquers sought to join a national honorary organization. When their search revealed no such organization existed, Elinor B. Watson, Robert Sloan, and Fairmont faculty director Paul F. Opp began researching how to create one.

Their efforts culminated in a proposed national constitution, and on August 12, 1925, the first cast of Alpha Psi Omega (ΑΨΩ) was initiated, drawing its members from the Masquers. Each chapter was designated a “cast,” and Fairmont State became the Alpha Cast. Soon after, Marshall College in Huntington, West Virginia, expressed interest and formed the Beta Cast. A member from Huntington suggested naming the national magazine “Playbill,” a title that was quickly adopted.

Within a year, Alpha Psi Omega grew rapidly, with 18 more casts established across the country. The first national convention, later known as the Grand Rehearsal, was held on December 27-28, 1926, at the Palmer House in Chicago, with 20 casts in attendance. These Grand Rehearsals occurred every five years until transitioning to an annual “National Meeting” held at the Southeastern Theatre Conference.

APO has long encouraged dramatic production at every stage of academic life. In 1929, in response to interest from junior colleges, Delta Psi Omega was established as the junior college division of Alpha Psi Omega. At the 1936 Grand Rehearsal, Delta Psi Omega (ΔΨΩ) was officially recognized, and today, over 350 Delta Psi Omega casts are active nationwide.

With more than 1,100 casts established since its founding, many of which remain active across the United States, APO/DPO has experienced continuous growth and remains the largest theatre honor society in the country. As of 2024, it stands as the only national theatre honor society in the United States. Colleges and universities with recognized academic standing and an established theatre program or club are eligible to form a cast.

In 1994, the building at Fairmont State University where Dr. Paul F. Opp founded APO (for four-year colleges), DPO (for two-year colleges), and the Thespian Society (for high schools, now the International Thespian Society) was added to the National Register of Historic Places in recognition of the profound impact of these organizations.

Today, APO/DPO are overseen by National Officers, a tradition established by leaders such as Paul F. Opp, Yetta Mitchell, Donald Garner, Jerry Henderson, and James Fisher. The current officers are Zackary Ross (President), Karin Maresh (Vice President), Sally Story (Business Manager), and Joel Lord (Web Administrator).