Understanding the relevance of anatomic and biomechanical principles is crucial when treating the face with soft tissue fillers to achieve a symmetric, soft, and natural-looking result while mitigating the risk of adverse events. The objective of this study is to summarize facial age-related effects, to relate them to facial biomechanics, and to establish guidelines for safe, effective, and esthetically pleasing full-face treatment following 3 basic principles while incorporating the latest scientific developments. This narrative review summarizes the current understanding of facial aging and its implications for facial biomechanics deduced from the authors’ experience and research.