The transitional years of early adulthood, with key tasks of identity and intimacy development, engender both opportunities and risks for well-being. We propose that the conceptualization and measurement of early adults' well-being can be improved through (a) an integration of ideas from developmental and psychological science on well-being, (b) the use of short, daily momentary assessments of well-being, and (c) a developmentally-informed examination of the structure of well-being within (and not just across) time. We developed a daily assessment of well-being based on the PERMA model (Seligman, 2011) and used network analysis to gain understanding from this data. Using Ecological Momentary Assessments, we assessed the five PERMA elements in college students' daily life and their network properties. Consistent with the PERMA model, network analysis showed items clustered around theorized elements and formed a unitary network of well-being. Consistent with developmental theory, we found that having positive relationships and positive emotion were most central to early adults' daily well-being.