This case study focuses on an annotated timeline analysis, also called timelining, used in a research project that examined preservice teachers’ learning trajectories of Technological Pedagogical Content Knowledge (TPACK) in an online educational technology course. While the project’s focus was on TPACK learning trajectories, the timelining could be used with any mixed methods study that is looking for factors that influence the development of a construct of interest over time. The timelining process is an innovative method of graphic elicitation that involves selecting, organizing, and analyzing data in order to record and deepen understanding of participants’ experiences over time. This research analysis method is extensively used in forensics, and recently it has started to appear in other disciplines, including education. In this case study, I will explain how I used digital timelining to select and organize preservice teachers’ experiences, online artifacts, and self-reported data along their TPACK learning trajectories in order to gain a deeper understanding of contextual and personal factors that led to variations in preservice teachers’ individual learning trajectories of TPACK.