Background: There is an increasing number of American workers that spend a larger portion of their time in occupations that involve primarily sedentary or light work. Physical activity has known benefits in lowering risk of chronic disease and improving overall health. However, most adults do not meet the recommended physical activity guidelines. The purpose of this dissertation study was to determine the relationship between the physical work environment, occupational activity, workplace characteristics, and physical activity in U.S. workers. Methods: This study included one systematic review and two cross-sectional studies using 2015 National Health Interview Survey data on sociodemographic, health behaviors, health outcomes, and occupational characteristics of adult workers. Findings: Overall, 25.2% of U.S. workers achieved sufficient leisure-time physical activity, and 27% in workers with low occupational activity. Age, male gender, higher education, higher income, normal BMI, workplace health promotion participation, and size of employer were associated with meeting leisure-time physical activity guidelines. In office workers, office and building designed for activity had the largest impact on physical activity among work environment characteristics. Conclusion: The study findings indicate that the workplace can positively influence sufficient physical activity by implementing active design practices, health promotion programs, and ensuring workers of all incomes and education levels have the opportunity to participate in these programs.