In 2004-05, the School District of Philadelphia (SDP) began a groundbreaking partnership with the Eli Broad Foundation to develop the Academy for Leadership in Philadelphia Schools (ALPS), one of several Broad-funded, alternative principal development programs initiated across the country. The ALPS effort was designed to respond to two challenges: (1) expected shortages in the supply of school leaders due to retirements, as well as limited succession planning, and (2) concerns about the quality of the leadership pipeline, particularly new principals' readiness for turning around low-performing district schools. Following a "pilot year" in 2004-05, ALPS underwent a variety of design changes, including the application and selection processes, seminar frequency and content, clinical experience, and coaching supports. As the second year of Philadelphia's effort to "grow its own" school principals got under way in spring 2006, so too did the Urban Education Collaborative's study of program implementation and outcomes, following closely the progress of Cohorts 2, 3, and 4, for the years 2005-06, 2006-07, and 2007-08, respectively. Over time, the program was dramatically altered and then abandoned after 2007-08. However short-lived the Philadelphia experiment, amidst growing interest and investment in alternative paths to principal development, ALPS offers a rich case study in both program design and implementation that can support similar efforts in other urban districts. The Academy of Leadership in Philadelphia Schools successfully graduated four cohorts of aspiring principals, including those from the pilot year. This evaluation study took a systematic longitudinal approach to understanding the process and outcomes of the initiative beginning with the second cohort. Both qualitative and quantitative data were used to support the conclusions that were drawn. All efforts were made to identify representative samples of participants for the interviews and observations. In addition, 72% of ALPS graduates participated in the survey. Even though a small minority of perspectives hypothetically remained unexpressed, every opportunity was made to enable participation of both a majority and range of participant voices. The evaluation identified several strengths of the program, including a well-defined curriculum, increasing selectivity, commitment to a diverse candidate pool, the yearlong residency, committed leadership and mentoring, and expert seminar presenters. On the other hand, ALPS could have benefited from a clearer theory of action about outreach to potential candidates, residency and principalship assignments, assessment of and feedback on participant progress, and ongoing supports. Also, because early outcome indicators suggested that factors may have negatively influenced program outcomes, more strategic data collection and use for continuous program improvement deserved new attention. Specific ALPS strengths and challenges and related recommendations are summarized. (Contains 1 figure.