This dissertation examines the beliefs, attitudes, and practices of Chief Student Services Officers (CSSOs) regarding the professional development of their middle managers (i.e., direct reports) within the Illinois Community College system. A sequential, mixed methods study was performed with CSSOs at Illinois community colleges across the state. In phase I of the study twenty-four of 48 CSSOs in Illinois completed an anonymous online survey about the professional development practices they encourage and provide their middle managers inside and outside of their institutions including barriers and challenges that make participation in professional development difficult. Six CSSOs volunteered to participate in the second phase of the study which consisted of in-depth, one-on-one interviews revealing more about how CSSOs' knowledge of adult learning principles influences their decisions about professional development of their middle managers. The study shows that CSSOs promote and support professional development of their middle managers in many ways and have "valued practices" that they rely upon. CSSOs rely on their knowledge of adult learning to establish appropriate conditions for learning among middle managers. Their knowledge of how individual learner characteristics impact learning and lead to effective outcomes from professional development is shaped by their familiarity with adult learning theories. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]