The second annual Poly Royal expanded to two days of celebration, offering visiting parents, alumni, prospective students and other visitors an increasing number of the school's programs and student achievements. In addition to its promotional aspects, the Poly Royal quickly became a high point in the campus social calendar. "Among the important school events are the annual Homecoming, Christmas party, May Day picnic, and the Poly Royal agricultural show," noted a 1934 student recruitment brochure entitled Your Vocational Opportunity.
In 1940, one of the original faculty organizers of the event, Carl "Gus" Beck, told a student reporter, "From the start the show met with public approval and has grown larger each year. Three years ago the constitution of the Associated Students was amended to enable Poly Royal to be an activity of the entire student body. Each year another event has been added to the list of Poly Royal events. Last year it was the student rodeo and this year came the relays " The 1944 event was downsized to a single day, while the 1945 Poly Royal was cancelled altogether due to gas rationing and other war-time restrictions.
With the war over, the annual "Country Fair on a College Campus" resumed its full schedule of events. Annual themes were often developed for the event, and guests of honor were chosen from among state officials, emeriti faculty, agricultural leaders, and other supporters of Cal Poly. In addition, as its reputation grew, Poly Royal actively targeted visitors and industry representatives statewide. The 1950 program announcement invited visitors to "come to San Luis Obispo, Heart of the Mission Trails and Home of the California State Polytechnic College" and promised "you'll have a wonderful time." President McPhee wrote, "For the 18th year it is a great pleasure to invite parents, alumni, and Cal Poly's many other friends to enjoy with us another Poly Royal celebration. I am proud of Poly Royal and of our students and faculty whose united efforts so vividly portray the unusual educational opportunities at this college. May we count on your coming?"
A popular custom was the selection of the Poly Royal Queen and her attendants, who reigned over the annual festivities. Jane Horton Bailey of San Luis Obispo was voted the first Poly Royal Queen at the second annual Poly Royal in 1934. During Cal Poly's years of all male enrollment, queens were chosen each year from area high schools or other colleges within the state.