We examined teachers' pedagogical reasoning for and the technological knowledge underlying their most-valued technology-supported activities for teaching and learning. Data from 140 preservice and 100 inservice teachers included open-ended, narrative responses to survey questions. Qualitative research methods guided analysis of the data that identified (a) the technology-supported activities and (b) the technical tools, target users, types of uses, rationales for use, and the TPACK underlying each activity. Preservice teachers described mostly teacher-focused and fewer student-focused techno-activities, and their reasoning for use focused on the technology's presentational and engagement effects. A majority of inservice teachers' techno-activities were student-focused, and their reasoning highlighted the technology's support for knowledge acquisition of higher-order cognitive skills and collaborative learning. The knowledge underlying all teachers' techno-activities was predominantly technological pedagogical knowledge (TPK), but inservice teachers also evidenced technological content knowledge (TCK). These results may reveal differences in the teachers' respective learning experiences in teacher education and professional development or reflect a professional maturation process in that it takes teachers time in the field as professionals to broaden their techno-activity repertoires to prioritize student-focus. Sharing the reasoning patterns in this study with teachers may assist them in developing deeper justifications for their technological work in the classroom.