Introduction: This study presents a unique case report of a 31 mm calcaneal spur, shedding light on the complexities of heel spur formation and its consequences. The connection between spur length and pain intensity remains uncertain, while factors such as obesity, biomechanical foot disorder, combined tarsal coalition, and loading patterns are implicated in their development. Case Presentation: A 38-year-old male with chronic plantar fasciitis and persistent heel discomfort presented with a congenitally shorter affected foot. Following initial medical attention for heel pain and an unidentified injection providing temporary relief, his symptoms worsened significantly over three months, reaching a distressing level of 8/10 on the pain scale. Morning and post-rest exacerbations were noticeably mitigated by activity. An X-ray revealed a 31 × 17 mm heel spur at the plantar calcaneal tuberosity with dysplastic rounded mortise and calcaneus. MRI showed evidence of extraarticular non-osseous talocalcaneal coalitions with degenerative changes in the angle of Gissane. It is possible that the patient’s problems are due to the initial coalition and secondary heel spur and plantar fasciitis. Conclusion: This rare case of a 31 mm calcaneal spur emphasizes the diagnostic value of advanced imaging in complex heel pain. While spur size alone may not predict symptoms, associated biomechanical and structural anomalies complicate management. Non-surgical treatments remain primary, but surgical options may be necessary for resistant cases. Further studies are needed to guide treatment strategies for unusually large spurs.