To what extent did he put into practice his philosophy of life when he was arrested and jailed in his novel Walden?

Thoreau indeed makes such an explicit statement at the end of his chapter, when he talks of being imprisoned for not paying his taxes to a state that supports slavery. (Though Massachusetts was a free state, it was required by federal law to enforce the Fugitive Slave Law and also benefited economically from the raw materials provided by the slave labor of the South, such as cotton used in Northern cloth factories.) That experience, of course, became the subject matter for the essay we now know as "Civil Disobedience. Walden Pond may be an intellectual refuge for Thoreau but only two miles from Concord, he cannot truly escape the demands of society.