Background: Hypertension is a leading cause of cardiovascular morbidity and mortality worldwide. Obesity, smoking, and prolonged disease duration are recognized risk factors for adverse cardiovascular outcomes; however, their combined impact on hypertension severity has not been adequately investigated in Bangladesh. Objective: To assess the impact of obesity, smoking, and duration of disease on hypertension severity among adult patients with primary hypertension. Methods: A total of 350 adults with primary hypertension were enrolled using consecutive sampling. Data on socio-demographic characteristics, body mass index (BMI), smoking status, and duration of hypertension were collected using a structured questionnaire and medical records. Hypertension severity was classified according to the JNC 7 criteria. Associations were assessed using the Chi-square test, and multivariable binary logistic regression identified independent predictors of severe hypertension (Stage 2 hypertension and hypertensive crisis). Results: The mean age of participants was 55.9±11.8 years, and 58.0% were male. Overall, 37.1% were obese, 32.0% were current smokers, and 27.2% had hypertension for more than 10 years. Hypertension severity was significantly associated with BMI (p<0.001), smoking status (p=0.001), and duration of hypertension (p<0.001). After adjustment for age and sex, obesity (AOR=2.84, 95% CI: 1.68–4.80), current smoking (AOR=2.17, 95% CI: 1.29–3.64), hypertension duration >10 years (AOR=4.26, 95% CI: 2.28–7.97), and increasing age (AOR=1.02, 95% CI: 1.00–1.04) were independent predictors of severe hypertension. Conclusion: Obesity, current smoking, longer disease duration, and increasing age were independently associated with greater hypertension severity. Lifestyle modification, smoking cessation, and long-term blood pressure control are essential to reduce disease progression and cardiovascular complications.