The digitalisation of our societies has made data ubiquitous, capturing the behaviors of individuals through their interactions with products, services, and systems. As design and HCI researchers increasingly integrate data throughout human-centered and participatory design processes, the highly dynamic nature of behavioral data reveals its deep interconnection with people, their behaviors, and experiences. Data-Centric Design leverages data as material for subjective inquiry–an entry point to better understand human dynamics through deeper reflection in research and design processes. This Research Topic aims to collect emerging, illustrative projects from the community, share the messiness of research and design processes with data, and surface good practices for effective and responsible data use. This need emerged from the guest editors' engagement in a series of Special Interest Group (SIG) meet-ups (Gomez Ortega et al., 2023) and workshops (Lee-Smith et al., 2023) at the ACM conference on Human Factors in Computing Systems (CHI). [...]