The precautionary approach is a way to manage problems related to the uncertainty of scientific knowledge regarding potential serious harms and to enable decision-making under uncertainty with due diligence. I have developed a model of the essential structural elements of the application of the precautionary approach, particularly the precautionary principle in EU law, as a legal design pattern—a formalized presentation of the core generic features and processes of how the law successfully addresses recurring problems. The precautionary approach appears as a decision tree with weighting and balancing. It serves as an intervening rule to resolve inter-system conflicts between different action systems such as the economy, civil society, and ecological systems. It is related to other design patterns like the proportionality test, risk and impact assessment, and judicial review. Presenting the application of the precautionary approach as a legal design pattern facilitates interdisciplinary communication regarding the essential features of legally required problem-solving. Such a presentation enhances the problem-solving capacity of the application of the law beyond the legal domain, for instance, in improving digitalization efforts and enabling the integration of anticipatory quality controls of justice, legality and good governance into decision-making processes.