This study examined principal internship portfolios required by two universities for principal interns, focusing on principal interns' activity participation. At each institution, principal interns undertook at least one semester-long internship experience which required collaborative work with various education stakeholders. The internship was designed to allow participants to work closely with other educators in fostering school improvement by completing specific instructional and managerial tasks. This research examined these tasks and the nature and intensity of collaboration throughout the internship experience. Data collection involved examining the contents of the 28 principal internship portfolios, which provided evidence of completed instructional and managerial tasks. Data analysis examined the intensity of activity involvement; program evaluation, program implementation, and managerial leadership; classroom observation and teacher conferencing; job shadowing/professional development; and independent leadership. Results indicated that principal interns engaged in legitimate peripheral participation with wide variation in the amount of hours committed to this learning experience. During the activities, they provided guidance on important areas of instructional leadership associated with improved student learning. Seven recommendations for principal internship experiences are included. Data collection forms and data charts are appended. (Contains 13 references.) (SM)