The Accreditation Council for Graduate Medical Education recommends the structured portfolio as a preferred assessment tool for assessing all six of its core physician competencies. However, compared with other evaluation measures, it may be one of the most resource-intensive for learners and evaluators. Given the time and effort needed to properly develop mentors, train evaluators, and persuade learners, facilitation of the learning environment supporting a portfolio may be the most important variable determining its success or failure. The authors review the components necessary to successfully build and maintain a robust portfolio learning environment in a graduate medical education setting. These include gaining staff acceptance, staging implementation, enhancing learner participation, training mentors, choosing paper versus electronic formats, and selecting assessment methods. Their blueprint for implementing a portfolio is informed by their five-year experience with a portfolio rollout in one internal medicine residency, from 2006 to 2011.