Purpose: This study aimed to determine whether gender, age, and initial tooth hue impacted the effect of laser tooth whitening. Materials and Methods: Ninety-one subjects were enrolled in a laser tooth whitening study at Kaohsiung Medical University. Sensitivity was evaluated by asking the patients about any tooth sensitivity they experienced after the whitening procedures were performed. The LaserSmile tooth whitener, containing 35% hydrogen peroxide, was applied to the tooth surfaces of both arches from the central incisor to the second premolar, and the LaserSmile Twilite diode laser was applied to the same maxillary and mandibular teeth. After removal of the whitening gel, shade matching was immediately performed with the ShadeEye NCC Dental Chroma Meter. Patients were classified into the following groups: tetracycline stain, gender, age, and initial tooth hue. Only 5 of the 91 individuals had tetracycline staining. Results: The initial tooth shade and the amount of shade change showed no significant differences between female and male patients, but a significant difference was found between hue and age group. Conclusions: Teeth with hue A showed greater shade improvement than teeth with hue C and hue D. Whitening response was better in younger individuals, and gender was not a factor that affected the whitening response. Sensitivity is common during the whitening procedure but can be tolerated by the patients.