Talocalcaneal coalition is a frequent cause of painful rigid flatfoot in adolescents and young adults, resulting from congenital failure of segmentation with fibrous, cartilaginous, or osseous bridging of the subtalar joint. Clinical presentation typically coincides with skeletal maturation and includes hindfoot pain, recurrent ankle sprains, progressive stiffness, and characteristic planovalgus deformity. Although prevalence is likely underestimated, advances in imaging have improved recognition and characterization. Diagnosis relies on the integration of clinical findings with imaging, where computed tomography (CT) remains the reference standard, while magnetic resonance imaging (MRI) enables accurate detection of both osseous and non-osseous coalitions and associated soft-tissue changes. This narrative review aims to provide a comprehensive and updated synthesis of current concepts in talocalcaneal coalition, with specific focus on its clinical implications and contemporary management strategies. We critically analyze diagnostic pathways, including emerging modalities such as weight-bearing CT, and discuss evidence-based indications for conservative treatment, coalition resection, and arthrodesis. Particular attention is devoted to patient selection, prognostic factors, and evolving minimally invasive techniques. Current limitations and areas of controversy are highlighted, emphasizing the need for standardized imaging criteria and optimized treatment algorithms to improve long-term functional outcomes.