Background: Few studies have focused on the prevalence of obesity and hypertension among young people (ages 15–24). Aim: To characterise the prevalence of obesity and systolic hypertension in young people aged 15–24 years across Australia. Methods: Using data from the 2011–2012 Australian Health Survey, a national cross-sectional population-based survey, we included 2163 young people aged 15–24 years. Risk factors were estimated using multinomial logistic regression. Results: The prevalence of obesity increased from 8% to 15% through the ages of 15–24 among males, but the prevalence of overweight and obesity were both 14% for females across all age groups. Low levels of physical activity were a strong risk factor for obesity for both males (odds ratio (OR) 5.95, 95% confidence intervals (CI)1.83–19.36) and females (OR 3.20 95% CI 0.69–14.87). Low socioeconomic status was associated with obesity among females only (first quintile OR 4.65, 95% CI 1.97–10.99). Although the prevalence of hypertension was low (4% males, 3% females), the prevalence of high normal blood pressure was substantial, especially among males (28% males, 14% females). Conclusions: Overweight, obesity and high normal blood pressure were highly prevalent among Australian young people. Low levels of physical activity were identified as a risk factor for obesity for both male and females. Programmes targeting physical activity participation may need to be tailored differently for males and females, with a focus on females during early adolescence but early adult life for males.