This study sought to describe the characteristics of mastery in occupational therapy practice. A Delphi survey (i.e., an inquiry technique used to predict and define constructs [Linstone & Turoff, 1975]) of 33 occupational therapy experts was conducted to obtain their conceptions of the characteristics of occupational therapy mastery. Three master clinicians, identified by the expert respondents, were then interviewed to validate and illustrate the concepts of mastery identified in the Delphi survey. The results suggest that mastery is a combination of selected personal traits, creative and flexible judgment, the use of occupation as the foundation for practice decisions, and a strong commitment to occupational therapy practice. Further, mastery is expressed through a personal style that is unique to each clinical master.