The lateral arm flap is an alternative to the conventional radial forearm flap and has been widely used due to advancements in flap characteristics. Especially, the fasciocutaneous flap has been widely used in head and neck reconstruction due to its versatile characteristics and surgical feasibility. This flap has successfully undergone several useful modifications based on various anatomical studies. Here, the authors aimed to verify the versatility and reliability of free lateral arm flap reconstruction of numerous head and neck defects. Twelve patients (6 men and 6 women; mean age, 66 years) with various types of lateral arm flaps from May 2017 to April 2019 were included. The anatomical reconstruction area was widely distributed across the facial subunits, tongue and oral cavity, and hypopharynx, among others. The flap varied in size from 3 × 5 cm to 17 × 7 cm, and the average pedicle length was 5.58 cm. The versatility of the lateral arm flap enabled successful coverage of various defects in all cases. Among 12 patients, the donor site outcome was rated as excellent and good by 2 and 10 patients, respectively. Three patients complained of post-operative hypoesthesia, which was subsequently resolved. The lateral arm flap is a unique and extremely versatile soft tissue free flap. Its versatility facilitates continuous modification of the flap and its application in various areas in different forms with excellent contour outcomes. The authors successfully verified the evolving methods and advantages of lateral arm flaps in the treatment of various head and neck defects.