This study aimed to identify the lifestyle and comorbidity factors associated with sedentary behavior by diabetes mellitus (DM) status. A total of 17,832 participants aged ≥50 years from the Korea National Health and Nutrition Examination Survey were included. Factors associated with long sedentary time (LST, ≥420 min/day) in individuals with and without DM (non-DM) were assessed. Among individuals with DM, LST was independently associated with excessive alcohol drinking (OR, 1.34; 95% CI, 1.02–1.74) and cardiovascular disease (OR, 1.47; 95% CI, 1.16–1.85). In individuals without DM, cancer (OR, 1.24; 95% CI, 1.06–1.44) and past smoking (OR, 1.16; 95% CI, 1.01–1.35) were independently associated with LST. Obesity (DM: OR, 1.28; 95% CI, 1.05–1.54; non-DM: OR, 1.24; 95% CI, 1.11–1.37), insufficient aerobic exercise (DM: OR, 1.55; 95% CI, 1.30–1.84; non-DM: OR, 1.50; 95% CI, 1.37–1.63), current smoking (DM: OR, 1.51; 95% CI, 1.11–2.05; non-DM: OR, 1.23; 95% CI, 1.05–1.45), and arthritis (DM: OR, 1.28; 95% CI, 1.04–1.56; non-DM: OR, 1.15; 95% CI, 1.04–1.27) were consistently associated with LST regardless of DM status. To reduce sedentary behavior time, it is important to consider an individual’s diabetes status and adopt a personalized approach.