Experience sampling methods are essential tools for building a modern idiographic approach to understanding personality. These methods yield multiple snapshots of people's experiences over time in daily life and allow researchers to identify patterns of behavior within a given individual, rather than strictly identify patterns of behavior across individuals, as with standard nomothetic approaches. In this article, we discuss the origin and evolution of idiographic methods in the field of personality and explain how experience sampling methods function as modern day idiographic methods in this field. We then review four primary ways in which experience sampling methods have been used to foster idiographic approaches in personality research. Specifically, we highlight approaches that examine individual differences in temporal and behavioral distributions, situation–behavior contingencies, daily processes, and the structure of daily experience. Following a brief methodology primer, we end by discussing future directions for idiographic experience sampling approaches in personality psychology and beyond.