Hardman ran for and was elected to a seat in the Georgia General Assembly in 1902 as a Representative of Jackson County. In 1907 he was elected Senator, and in 1909 was re-elected as Representative. Hardman was an active legislator; he introduced legislation which required public schools to offer basic agricultural courses, established the State Board of Health, provided free treatment for individuals with hydrophobia, utilizing the 'Pasteur method', prohibited the production, sale, and consumption of alcohol, considered to be an early victory in the national Prohibition movement, and petitioned the United States Congress to commission a drainage survey for the state.