This study examined how online discussion of the classroom challenges that preservice teachers face during the field experience can lead to problem solving and knowledge generation. Drawing upon Horn and Little's (2010) descriptions of generative discourse, the study examined how a community of preservice teachers, their university supervisors, and other experts engaged in problem solving and the generation of abstract teaching principles through an online discussion forum. Analysis of discussion threads related to classroom challenges revealed four distinct patterns of discourse as preservice teachers attempted to solve problems of practice. Preservice teachers used the space to link to and borrow from experts' experiences and reflect on broader principles of teaching. Experts used the online space to specify the nature of the stated challenges and connect those challenges to broader theoretical perspectives. The findings suggest how experts can promote generative discourse in online discussion to support preservice teachers in problem solving and application of abstract teaching principles as they build a foundation for effective future practice.