Background : Mallet finger is a frequent injury to the terminal extensor mechanism of the distal interphalangeal (DIP) joint, often caused by an avulsion fracture of the dorsal base of the distal phalanx. While conservative treatment using splints remains the standard for uncomplicated soft-tissue mallets, surgical fixation becomes necessary in cases with volar subluxation or large articular fragment involvement. Extension-block pinning, introduced by Ishiguro, has evolved into a reliable, minimally invasive technique that ensures accurate joint congruity and early rehabilitation. Aim: The objective of this study was to evaluate the functional and radiological outcomes of extension-block pinning in patients with bony mallet finger treated by Department of Orthopaedics at Government Medical College Srinagar. Methods: A prospective observational study was conducted between January 2022 and June 2024 on 15 patients (10 males, 5 females) aged 18–55 years (mean = 32.8 ± 9.6 years). Inclusion criteria were acute bony mallet finger with articular surface involvement greater than 30% or displacement more than 2 mm, and absence of previous finger deformity. Under digital block anesthesia and fluoroscopic guidance, a 1.0–1.2 mm K-wire was introduced percutaneously for extension-block fixation, followed by a trans-DIP wire for stabilization. Post-operative immobilization was maintained for 6 weeks, followed by gradual mobilization and physiotherapy. Clinical evaluation was based on Crawford’s criteria, measuring extension lag, flexion range, and total active motion. Radiological union, subluxation correction, and complications were assessed. Results: All 15 patients achieved radiographic union at a mean of 6.4 ± 1.1 weeks. Mean follow-up was 12.5 months (range 10–15 months). Mean extension lag improved from 27.3° pre-operatively to 4.6° at final follow-up, while mean DIP flexion was 68.2° ± 8.1°. Mean total active motion was 72.8° ± 7.4°. According to Crawford’s criteria, results were excellent in 9 patients (60%), good in 4 (26.7%), fair in 1 (6.7%), and poor in 1 (6.7%). Complications included two cases (13.3%) of superficial pin-tract infection managed conservatively and one case (6.7%) of transient nail deformity; no non-union or residual subluxation was observed. Conclusion: Extension-block pinning provides excellent functional and radiological outcomes in selected cases of bony mallet finger, with minimal complications and high patient satisfaction. This technique remains a reliable, cost-effective option in the management of displaced mallet fractures, particularly in resource-limited settings such as tertiary hospitals in developing regions.