The POSSE was formed in 1964 by five OSU graduates with the premise of helping persuade young football talent to attend OSU. The first meeting was held in 1964 at Whit’s Café in Oklahoma City. The five decided on the name “The Posse Club” and elected officers. They began having meetings and charging dues to increase membership and raise money. The “Deputy” was the president, while the officers and board of directors were the “Sheriffs.”

When former Cowboy coach and wrestling great Myron Roderick became the Oklahoma State Athletic Director, the Posse organization was recognized as a means for fundraising for all sports and became an official part of the Athletic Department. Later, an acronym was created from the letters in the word POSSE: Providing Opportunities for Scholastic and Sports Excellence. This clever credo encompasses the organization's goals of helping the Cowboys and Cowgirls compete at the highest level, both on the field and in the classroom.

Nearly 45 years later, the OSU POSSE is 8,200 members strong and growing. Several of the original members remain loyal season ticket holders and strong donors to the organization they pioneered.