Phillips was born in London. Following some political difficulties in Leicester where he was a schoolteacher and bookseller, he returned to London, established premises in Paternoster Row, St. Paul's Churchyard, and founded The Monthly Magazine in 1796; its editor was Dr. John Aikin, and among its early contributors were fellow radicals William Godwin and Thomas Holcroft. He built up a prominent fortune based on the speculative commission of newly revised textbooks and their publication, in a competitive market that had been freed by the House of Lords' decision in 1777 to strike down the perpetual copyright asserted by a small group of London booksellers to standard introductory works. His Juvenile Library published in 1800–03 provided the steady returns of all successful children's books. By 1807 he was in sufficient standing to serve as a Sheriff of London, at which time he was knighted on the occasion of presenting an address. Another of the contributors to Phillips' Monthly Magazine was the Scottish novelistJohn Galt. Angela Esterhammer has suggested that the character Masano, an irascible Italian printer in Galt's Andrew of Padua, the Improvisatore, is based on Phillips. Phillips overextended himself and was declared bankrupt in the Bank Panic. He died in Brighton and is buried in the western extension of St Nicholas' Churchyard. He was a vegetarian.
He was the author, under his own name, of On the Powers and Duties of Juries, and on the Criminal Laws of England, 1811; A Morning's Walk from London to Kew, 1817; A Personal Tour Through the United Kingdom, 1828. Many of his further works were published under at least five pseudonyms including David Blair. His own political leanings, evinced in Golden Rules of Social Philosophy, Or, A New System of Practical Ethics encouraged him to publish works by the radical jobbing writer of educational texts, Jeremiah Joyce, though often under pseudonymous disguises; Rees and Britten asserted in their Reminiscences of Literary London that many works were written by Phillips and attributed to well-known writers, who oversaw the proofs and put their names to the manuscripts, for remuneration. Joyce was the actual author of Gregory's Encyclopedia published by Phillips.
