With Alfred Austin, his junior by six years, he helped to found a Mechanics' Institute at Leeds, at which he lectured on literary subjects.
He found early employment as dramatic critic for the Literary Gazette, through a chance meeting with the editor John Morley.
[2] In 1871, during the siege of Paris, Knight used his influence to secure the invitation to the Comedie Française to act at the Gaiety Theatre in London.
At Marston's house he met authors and playwrights; Thomas Purnell introduced him to Swinburne, to whom and Dante Gabriel Rossetti he became close.
[2] Knight contributed the causerie signed "Sylvanus Urban" to the Gentleman's Magazine from 1887 till near his death, and he was a reviewer of general literature for the Athenæum.
A posthumous portrait in oils by Margaret Grose was presented to the Garrick Club in 1912 by Knight's friend Henry Benjamin Wheatley.
[2] Knight wrote on theatre history, and was the main contributor of the lives of actors to the Dictionary of National Biography, first edition and first supplement.
He published in 1893 Theatrical Notes 1874-1879 (1893), a collection of articles on the drama from the Athenæum, and he edited in 1886[3] the Roscius Anglicanus of John Downes.