Arthur was born at Bodmin in Cornwall to the union of two ancient local families, the Quiller family and the Couch family and was the third in line of intellectuals from the Couch family. His younger sisters Florence Mabel and Lilian M. were also writers and folklorists ( The Age). His father, Dr. Thomas Quiller Couch (d. 1884), was a noted physician, folklorist and historian (see The Gentleman's Magazine). His grandfather, Jonathan Couch, was an eminent naturalist, also a physician, historian, classicist, apothecary, and illustrator (particularly of fishes) in the style of the time. His son, Bevil, was a war hero and poet, whose romantic letters to his fiancée, the poet May Wedderburn Cannan, were published in the beautiful but tragic Tears of War. He also had a daughter, Foy Felicia, to whom Kenneth Grahame inscribed a first edition of his The Wind in the Willows attributing Quiller-Couch as the inspiration for the character Ratty, auctioned by Bonhams on Tuesday 23 March 2010 for £32,400.

He was educated at Newton Abbot College, at Clifton College, and Trinity College, Oxford and later became a lecturer there.

On taking his degree in 1886 he was for a short time classical lecturer at Trinity. After some journalistic experience in London, mainly as a contributor to the Speaker, in 1891 he settled at Fowey in Cornwall.

In Cornwall he was an active worker in politics for the Liberal Party. He was knighted in 1910.

Quiller-Couch was made a Bard of Gorseth Kernow in 1928, taking the Bardic name Marghak Cough ('Red Knight'). He was Commodore of the Royal Fowey Yacht Club from 1911 until his death.

While he was at Oxford he published (1887) his Dead Man's Rock (a romance in the vein of Robert Louis Stevenson's Treasure Island), and he followed this up with Troy Town (1888) and The Splendid Spur (1889). Quiller-Couch is well-known for his story "The Rollcall of the Reef",[1] based on the wreck of the HMS Primrose in 1807.

He published in 1896 a series of critical articles, Adventures in Criticism, and in 1898 he completed Robert Louis Stevenson’s unfinished novel, St. Ives.

From his Oxford days he was known as a writer of excellent verse. With the exception of the parodies entitled Green Bays (1893), his poetical work is contained in Poems and Ballads (1896). In 1895 he published an anthology from the 16th- and 17th-century English lyricists, The Golden Pomp, followed in 1900 by the Oxford Book of English Verse, 1250—1900 (1900). (Later editions of this extended the period covered up to 1918 and it remained the leading general anthology of English verse until Helen Gardner's New Oxford Book of English Verse appeared in 1972.) (Of the original edition nearly half a million copies were issued according to the introduction to the NOBEV, 1972. The extended edition appeared in 1939.)

In 1910 he published The Sleeping Beauty and other Fairy Tales from the Old French. He was the author of a number of popular novels with Cornish settings (collected edition as 'Tales and Romances', 30 vols. 1928—29).

He received a professorship of English at the University of Cambridge in 1912, which he retained for the rest of his life, later holding a Chair (or Professorship) of English. Simultaneously he was elected a Fellow of Jesus College, which he held until his death. His rooms were on C staircase, First Court, and known as the 'Q-bicle'. He oversaw the beginnings of the English Faculty there, an academic diplomat in a fractious community. He is sometimes regarded as the epitome of the school of English literary criticism later overthrown by F. R. Leavis.

Alistair Cooke was a notable student of Quiller-Couch and he features prominently in Nick Clarke's semi-official biography of Cooke. He also notes that Quiller-Couch was regarded by the Cambridge Establishment as "rather eccentric" even by the University's standards.

Quiller-Couch was a noted literary critic, publishing editions of some of Shakespeare's plays (in the New Shakespeare, published by Cambridge University Press, with Dover Wilson) and several critical works (among these are Studies in Literature (1918) and On the Art of Reading (1920)). He edited a successor to his verse anthology: Oxford Book of English Prose which was published in 1923. He left his autobiography, Memories and Opinions, unfinished; it was nevertheless published in 1945.

His Book of English Verse is oft-quoted by John Mortimer's fictional character Horace Rumpole.

Castle Dor, a retelling of the Tristan and Iseult myth in modern circumstances, was left unfinished at Quiller-Couch's death and was completed many years later by Daphne du Maurier. As she wrote in the Sunday Telegraph on April 1962, she took up the job with considerable trepidation, at the request of Quiller-Couch's daughter and "in memory of happy evenings long ago when 'Q' was host at Sunday supper"

He features as a main character, played by Leo McKern, in the 1992 BBC TV feature, The Last Romantics. The story focuses on his relationship with his protegé, F. R. Leavis and the students.

His Cambridge inaugural lecture series, published as On the Art of Writing, is the source of the popular writers' adage "murder your darlings".

Fiction

• Dead Man's Rock (1887)
• Troy Town (1888)
• The Splendid Spur (1889)
• The Blue Pavilions (1891)
• St Ives (1898), completing an unfinished novel by Robert Louis Stevenson
• The Ship of Stars (1899)
• Hetty Wesley (1903)
• The Adventures of Harry Revel (1903)
• Fort Amity (1904)
• The Shining Ferry (1905)
• Sir John Constantine (1906)

A collected edition of Q's fiction appeared as Tales and Romances (30 volumes, 1928—29)

Verse

• Green Bays (1893)
• Poems and Ballads (1896)

Criticism and anthologies

• Adventures in Criticism (1896)
• The Golden Pomp, (1895)
• Oxford Book of English Verse, 1250—1900 (1900)
• The Sleeping Beauty and other Fairy Tales from the Old French (1910)
• The Oxford Book of Ballads (1911)
• Studies in Literature (1918)
• On the Art of Reading (1920)
• On the Art of Writing (1916)
• Oxford Book of English Prose (1923)

Autobiography

• Memories and Opinions (unfinished, published 1945)