His printing office was well supplied with good type in all sizes, from nonpareil to great primer, and he had a fine range of initial letters, ornaments and borders.
When Henry Bynneman died in 1583, he appointed Denham and Ralph Newbery to be his executors.
Shortly after this it is thought that Denham started the Eliot's Court Printing House.
Denham was an industrious printer and in 1583 was returned as having four presses; in 1586-7 and 1588-9 he served as Junior Warden of the Stationers' Company, but he never became Master.
Denham invented the rhetorical question mark "⸮", which did not become a permanent part of the language.