In this study, I argue that those in the field of composition need to reclaim the important work of graduate student writing teachers and the introductory courses they teach. By conducting this feminist poststructural case study, I sought to add to current conversations about teacher knowledge and professional learning by affording graduate students the opportunity to "speak" as teachers and to discuss their developing professional subjectivities. Based on my analysis of writing TAs' understandings of teacher knowledge and professional learning, I drew the following conclusions: (a) teacher knowledge is intimately tied to TAs' own areas of study and is not necessarily linked to the content they are teaching (1st-year writing); (b) this disconnect between TAs' areas of study and their teaching positions within the University Writing Program creates tension between their subjectivities; (c) this tension may be problematic or productive in how TAs understand student writers; and (d) the changes writing TAs made to their second semester syllabi indicate that they were seeking ways to reconcile their teacher knowledge with the Writing Program's perspectives. The findings of this study indicate that providing opportunities for critical teacher reflection may serve to bring attention to introductory composition courses, the work of graduate instructors, and the learning for undergraduate students. [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.]