In 1926, Cardinal Key was founded to recognize outstanding leaders at Iowa State University. The structure and philosophy of Cardinal Key were modeled after a similar honorary known as Blue Key at Yale University. Cardinal Key was originally established as a men's senior honorary until 1975, when it expanded its charter to recognize outstanding women leaders on campus.

Cardinal Key was founded upon the cardinal virtues of leadership, service, scholarship, and character. These four ideals continue to guide the organization. Our constitution states it in this way: Cardinal Key shall be empowered to recognize, by membership, Iowa State University students, faculty, and staff whose leadership in university activities has been exemplary, whose scholarship is of high standing, whose character is above reproach and whose service to the university community has been outstanding; and by serving as a unifying body of campus leaders, Cardinal Key will exist to promote the cardinal virtues within the university community.