This paper introduces a user-centered design process and case study evaluation of a novel wearable visualization system for team sports, coined TeamAwear. TeamAwear consists of three basketball jerseys that are equipped with electroluminescent wires and surfaces. Each jersey can be wirelessly controlled to represent game-related information on the player in real-time, such as the amount of individual fouls, scores and time alerts. A participatory user-centered approach guided the development process towards a more meaningful, ethically and ergonomically valid design. The system aims to enhance the awareness and understanding of game-related public information for all stakeholders, including players, referees, coaches and audience members. We initially hypothesized that such increased awareness would positively influence in-game decisions by players, resulting in a more interesting and enjoyable game play experience for all participants. Instead, the case study evaluation demonstrated TeamAwear’s perceived usefulness particularly for non-playing stakeholders, such as the audience, referees and coaches, supporting more accurate coaching assessments, better understanding of in-game situations and increased enjoyment for spectators. The high amount of game-related cognitive load on the players during game-play seems to hinder its influence on in-game decisions.