Vocal fold paralysis is a rare but functionally limiting side effect of radiation treatment for breast cancer. The current case study documents the management of a 79-year-old woman who presented with vocal fold palsy after radiation treatment for breast cancer more than 10 years previously. Treatment before the current case report involved a failed attempt of surgical intervention which was followed by a period of traditional behavioral voice therapy that had no discernible impact on either vocal fold function or voice quality. The Lee Silverman Voice Treatment (LSVT) was subsequently conducted to determine if intensive behavioral voice treatment could achieve a behavioral change. Endoscopic evaluation of laryngeal function as well as acoustic and perceptual voice assessments were conducted before, after, and at 6 months after the LSVT. After treatment, there was increased compensatory movement of the unaffected vocal fold, improving approximation to the paralyzed vocal fold. Acoustic and perceptual assessments also revealed small but clinically significant increases in perceptual voice quality, vocal loudness, and overall intelligibility. Despite the chronic nature of the vocal fold paralysis in this case, the case study demonstrates that intensive voice treatment using the LSVT helped to achieve a small but positive impact on both vocal fold function and voice quality.