Agency is a central concern of gerontology, age studies, and life course research, but the role of literate action in supporting and perpetuating agency in older adult writers is not well understood. A conceptual framework for the relationship between agency and literate action would provide important insight into contemporary writing research on older writers. In this study, I trace the literate practices of one writer, Frank, in order to understand how he used literate action to both negotiate his lifeworlds and support his own agency in his life after his retirement from an engineering career. Drawing on posthumanist understandings of agency, I use a combination of sociohistoric (Erickson and Roozen) and sociological (Brandt) methodologies to trace Frank’s literacy history, the chronotopes for writing that he enacts, and the agency that he develops and supports through that chronotopic work. I focus in particular on the acts of textual coordination that Frank enacts, using those data points to understand how Frank creates objects in his daily writing that bolster his agency in future social situations—a concept I refer to as expansive agency.