He worked as a lawyer until he was elected to the Massachusetts House of Representatives where he served from 1827 to 1833.
Mann married Charlotte Messer in 1830 but she died 2 years later.
In 1835-1837 he worked in the Massachusetts Senate. Mann was appointed in 1837 to the Massachusetts State Board of Education and served as secretary for the organization. Thus, began his life-long interest in education and the improvement of the system.
Mary Peabody became his second wife in 1843. They honeymooned in Europe with the Samuel Howes’ family but it was also a working trip. Mann observed schools in Prussia and later convinced Massachusetts to adopt an educational system based on the Prussian model.
Mann has been called the “Father of the Common School Movement.” He supported the ideas of universal public education and teachers being trained in normal schools. He believed this was the best way to help children become thoughtful citizens of the republic.
Some of his other beliefs were: education should be paid for by the public, students should come from a variety of backgrounds, education should be non-sectarian, and well trained professional teachers should be provided.
Mann worked for longer school years, a wider curriculum, higher pay for teachers, and better equipped school houses. He wanted a common learning experience for all children no matter their social class. Mann considered building a person’s character as important as academics.
He convinced his home state to build public school buildings and normal schools to train professional teachers.
Horace and Mary Peabody Mann had 3 sons: Horace, George, and Benjamin.
In 1852 Mann was nominated for governor of Massachusetts and offered the position of president of Antioch College in Yellow Springs, Ohio. He failed to be elected governor and so accepted the college presidency. He taught theology, economics, and philosophy at the college. He was also a popular lecturer throughout the Midwest.
Shortly before his death Mann delivered the 1859 commencement address at Antioch. In the speech he exhorted the graduates to “be ashamed to die until you have won some victory for humanity.”
Mann died Aug. 2, 1859 at Yellow Springs, Ohio. He is buried at North Burial Ground, Providence, R.I., next to his first wife.