This paper offers detailed analysis of ethnographic data concerning an adult literacy student producing and discussing a text about China, using the framework for investigating the discoursal construction of writer identity developed by Burgess and Ivanic (2010). It sheds light on how writer identity changes and develops over time by showing how different aspects of identity and different timescales come into play during one act of writing. The analysis reveals the possibilities for and constraints upon change and development contained within that act and enriches understandings of how a single writing activity can contribute to writing development. (Contains 4 figures.)