In this article, the authors discuss the Lilead Fellows Program, funded by a grant from the Institute of Museum and Library Services (IMLS). This innovative approach to professional development (PD) is for school district library supervisors. It is based upon widely accepted principles of quality PD, and is in its second year of operation with an initial cohort of twenty-five Lilead Fellows, school district library supervisors selected through a competitive application process. The design of the fellows program is based upon research findings (Birman et al. 2000; Garet et al. 2001; Guskey and Yoon 2009; Peterson 2002; Day 1993) that state that effective PD programs for educators reflect the following principles: (1) Extensive time in PD activities is complemented with sufficient opportunities for follow-up after the PD sessions are over; (2) The content has a sharp focus on the daily activities of educators; (3) Committed and knowledgeable mentors and/or coaches guide PD participants; (4) Information technology is used to promote continued engagement; and (5) Personal reflections are expressed in writing and by other means. The Lilead Fellows Program provides a long-term experience that allows time for extended learning and application, requires each participant to focus on an important and personally relevant issue, uses experienced and passionate mentors, incorporates technology to foster community and learning, and makes sure fellows reflect and think critically about their work and the field as a whole.