Background/Objectives: Telehealth has promising opportunities for hypertension management through remote monitoring and enhanced patient–provider communication. However, the usability of these services may vary across patient populations, particularly with respect to age and clinical complexity. This study examined the association of age and specific comorbidity categories with perceived telehealth usability among patients with hypertension in Saudi Arabia. Methods: An analytical cross-sectional study using questionnaire data linked with retrospective electronic health-record information was conducted among adults with physician-diagnosed hypertension who received telehealth follow-up following hospital discharge. Participants completed the Arabic version of the Telehealth Usability Questionnaire (TUQ). Sociodemographic and clinical data were extracted from electronic health records. Age in years was entered as a continuous variable in the primary multivariable model, while age group was examined as a categorical sensitivity analysis. Comorbidity was entered as a nominal categorical variable using hypertension only/no additional comorbidity as the reference group. Because group variances were heterogeneous, Welch’s ANOVA and Games–Howell post-hoc comparisons were used for group comparisons. Results: We included 266 adults with physician-diagnosed hypertension. Mean age among the 265 participants with valid age entries was 48.38 years (SD 18.80), and 56.0% were female. The mean total TUQ score was 93.11 ± 21.58, corresponding to a mean item score of 4.43 ± 1.03. According to the prespecified mean-item scoring framework, this represented moderate perceived usability. Significant differences were observed across age groups (Welch’s F(5,46.07) = 8.96, p < 0.001; η² ≈ 0.177), with the highest mean TUQ score among participants aged 20–30 years (110.75 ± 31.72) and the lowest among those aged >70 years (82.53 ± 7.33). In the corrected multivariable model, age was inversely associated with the TUQ score (B = −0.357, 95% CI −0.525 to −0.190; p < 0.001; β = −0.314). Compared with hypertension only/no additional comorbidity, the “other comorbidities” group had higher TUQ scores (B = 23.292, 95% CI 12.392–34.192; p < 0.001), whereas diabetes, chronic kidney disease, and respiratory conditions were not independently associated with the TUQ score. Conclusions: Perceived telehealth usability among patients with hypertension varied according to age and specific clinical characteristics. Older age was associated with less favorable usability perceptions, whereas the pattern across comorbidity categories was heterogeneous rather than uniformly positive or negative. These findings support age-sensitive, patient-centered telehealth design and targeted usability support for clinical subgroups experiencing greater barriers to digital care.