Free tissue transfer has become the preferred option for complex reconstructions in head and neck cancer ablation. This study reviewed the surgical outcome and analyzed the evolution of microsurgical head and neck reconstruction over 20 years in single institute. A total of 1,918 patients underwent microsurgical head and neck reconstructions in 20-year period. The surgical outcome and complications among these 2,019 flaps (1,223 anterolateral thigh flaps, 372 fibula flaps, 353 radial forearm flaps, 12 jejunal flaps, and 59 others) were retrospectively reviewed and analyzed. A total of 201 cases required emergent surgical re-exploration and the overall flap success rate was 96.2%. Venous insufficiency was the most common cause for re-exploration. Other major complications included fistula formation (5.4%), partial flap necrosis (7.5%), and infection (17.8%). The fibula flap had frequent complications compared with soft tissue flaps. The familiarity to the ALT flap had minimized complications and allowed for widely versatile uses. Free tissue transfer is shown to be highly reliable option for head and neck reconstruction. For soft tissue defect, ALT flap is the first choice. Fibula flap is ideal for bone defect reconstruction. In case of complex composite defects, double flaps, which include ALT and fibula flaps could reconstruct bone and soft tissue defects simultaneously with high success rate.