Because the tongue consists of 26 intrinsic and extrinsic muscles, even hemiglossectomy, which preserves some of the tongue and its muscles, leads to functional morbidity in speech and swallowing. Subsequent reconstruction using a conventional fasciocutaneous flap results in limited functional recovery. This study compared the functional recovery of patients who underwent hemiglossectomy based on the fasciocutaneous free flap with or without dynamic gracilis muscle flap reconstruction. Twenty-three patients were included in the study. Reconstruction was achieved using radial forearm and gracilis conjoined flaps (n = 7), gracilis flaps (n = 7), and radial forearm flaps (RFFFs) (n = 9) between 2014 and 2019. Functional outcome data were collected via videofluoroscopic swallowing, speech analysis, and a tongue movement scale. In the conjoined flap group, the lingual range of motion in terms of elevation and defect-side lateralization was superior to that of the RFFF group. Furthermore, the conjoined flap was associated with superior protrusion, elevation, and lateralization (on both sides) than the gracilis-only flap. Patients who underwent conjoined-flap reconstruction had better articulation, intelligence, and dysphagia outcomes than patients who underwent reconstruction with RFFFs or gracilis-only flaps. Although this was a preliminary study, the findings suggest that using a conjoined free flap with an RFFF and a functional gracilis muscle flap for dynamic hemitongue reconstructions could improve postoperative tongue function.