This paper explores the university supervisor's role in the Professional Development School (PDS) context, examining the influence of the PDS context on one student teacher supervisor's practice at Penn State University and the surrounding school district. The primary vehicle around which the PDS was structured was a 1-year internship for senior undergraduates who spent that time in an elementary school. Data came from the supervisor's daily journal, field notes, observations, and conference notes. He found that several factors appeared to be quite different in the PDS versus traditional context, including: readiness building; relationships with mentors, interns, and children; stages of development in reflective supervision over time; his knowledge of and focus on individual children; his encouragement of interns to progress at an individually appropriate pace; and the role of goal setting and evaluation. Being able to spend significant time over 1 year with interns and mentors significantly altered their relationships, allowing him to become a co-teacher and colleague as well as a supervisor. He was able to focus the supervisory process on individual children as well as children as a whole. He believes that his effectiveness as a supervisor increased in the PDS context. (Contains 15 references.) (SM)