In the 1790s Johnson aligned himself with the supporters of the French Revolution, and published an increasing number of political pamphlets in addition to a prominent journal, the Analytical Review, which offered British reformers a voice in the public sphere. In 1799, he was indicted on charges of seditious libel for publishing a pamphlet by the Unitarian minister Gilbert Wakefield. After spending six months in prison, albeit under relatively comfortable conditions, Johnson published fewer political works. In the last decade of his career, Johnson did not seek out many new writers; however, he remained successful by publishing the collected works of authors such as William Shakespeare.
Johnson's friend John Aikin eulogized him as "the father of the booktrade" and he has been called "the most important publisher in England from 1770 until 1810" for his appreciation and promotion of young writers, his emphasis on publishing cheap works directed at a growing middle-class readership, and his cultivation and advocacy of women writers at a time when they were viewed with scepticism.