We present the case of a 36-year-old male patient with a posttraumatic composite defect of the lower two-thirds of the anterior aspect of the left leg with exposed necrotic tibia in an old, neglected type 3b fracture of the tibia of 9-month duration. The options for definitive soft-tissue cover include microvascular free tissue transfer and cross-leg flaps. In trauma cases, the surrounding tissue is usually damaged, and the recipient vessels are frequently implicated, ruling out the use of a microvascular free flap. Cross-leg flaps are unachievable due to large defect sizes and lack of appropriate donor tissue. In this case report, we highlight the use of cross-leg microvascular free anterolateral thigh (ALT) flap cover for the composite leg defect. By presenting our case, we aim to advocate the clinical application of cross-leg free flap surgery in vessel-depleted limbs as a safe and viable option.