Free text forms of clinical documentation stored in electronic health records contain a trove of data for researchers and clinicians alike. However, often these data are challenging to use and not easily accessible. EMERSE, a clinical documentation search and data abstraction tool developed by the University of Michigan, helps users in the task of searching through free text notes in clinical documentation. This study evaluates the usability and user experience of the EMERSE system, and draws inferences for the design of such systems. The study was conducted in 3 phases. In Phase 1, interviews with site administrators investigated factors that facilitate or hinder the implementation and adoption of EMERSE. Phase 2 employed semi-structured interviews to understand the uses, benefits, and limitations of the system from the perspective of experienced users. In Phase 3, system-naive users performed a set of basic workflow tasks, then completed post-activity questions and surveys to evaluate the intuitiveness and usability of the system. Participants rated the system exceptionally high on usability, user interface satisfaction, and perceived usefulness. Feedback also indicated that improvements could be made in visual contrast, affordances, and scope of notes indexed. These results indicate that tools such as EMERSE should be highly intuitive, attractive, and moderately customizable. This paper discusses some aspects of what may contribute to a system having such characteristics.