This study collected information on the professional development of 177 senior student affairs officers (SSAO) at higher education institutions in the United States. The purpose of the study was to identify the professional development activities that these SSAOs engaged in to prepare for the role and the perceived effectiveness of those activities. The study used a set of eight competencies gathered from the literature to assess the professional development activities that SSAOs perceive prepared them for the role. A newly developed instrument was used to assess the usefulness of 11 common professional development activities in each competency area. The study used quantitative data analysis to determine the significance of these activities in preparing SSAOs for the role. The results showed these SSAOs found discussions with colleagues were perceived as the most effective form of professional development. These SSAOs cited a personally identified need to build knowledge, skill, or ability as their top reason for how they identified the professional development activities and favored professional development activities that were seen as highly relevant, valuable, and timely to their work. There were many differences in the perception of professional development activity effectiveness among the comparisons of personal characteristics of gender, race/ethnicity, institution type, and years of experience. The results of this study may be valuable to inform professional associations, institutions of higher education, and professionals who aspire to the SSAO role on what to offer or pursue for professional development. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]