Nu key bears the three Greek letters together with the eye of wisdom. Juniors, seniors and students in graduate and professional schools who rank in the top 15 percent of the their classes may be considered for membership. Each chapter can nominate no more than 4 percent of the junior and senior classes from each school or college of a university. The method of selection varies from campus to campus but is based always on scholarship, loyalty and service. Chapters may also initiate honorary members, persons who are not students in the school but who display the outstanding qualities sought in Alpha Sigma Nu members.
Activities vary from chapter to chapter.
Nu chapters have long-standing traditions of activity in such areas as orientation programs, tutoring services, honors convocations, leadership conferences, seminars, lecture series, outstanding teacher awards, reports to the university administration and community service. Other chapters limit activity to the annual selection and initiation of new members, recognizing those who prove themselves outstanding in their other campus activities. Alpha Sigma Nu sponsors a number of projects including the National Alpha Sigma Nu Book Awards for outstanding publications by faculty of the Jesuit colleges and universities. An endowment fund supports scholarships at member schools. The society publishes a national newsletter and belongs to the Association of College Honor Societies.