Digital literacy practices in multimodal interactional spaces, including video-mediated settings, are largely being recognized as a rich domain of research inquiry in pre-service language teacher education. This study presents findings from a telecollaborative partnership project in which small groups of pre-service language teachers collaboratively design, receive feedback for, implement, and reflect on telecollaborative tasks in and through video-mediated interactions. Using multimodal conversation analysis as the research methodology, the study describes on a micro-longitudinal basis how the collaborative design processes on an online task design tool, the DigiTask web app, create opportunities for pre-service teachers’ exploration of the technological affordances of video-mediated interaction while also interactionally managing the complex pedagogical, social interactional, and digital literacy practices in situ. More specifically, this study shows how pre-service teachers’ collaborative design-relevant actions facilitate the emergence of a digital literacy practice (i.e., shared control of a shared screen). Following the emergence of the practice, the teacher educator introduces the data-led evidence for the emergent practice in a large group video-mediated teacher education classroom, thus multiplying the practice within the larger scope of the project. The findings bring new insights into pre-service language teacher education and video-mediated interactions.