Coleridge was born on 21 October 1772 in the town of Ottery St Mary in Devon, England. Samuel's father was the Reverend John Coleridge (1718–1781), the well-respected vicar of St Mary's Church, Ottery St Mary and headmaster of the King's School, a free grammar school established by King Henry VIII (1509–1547) in the town. He had previously been Master of Hugh Squier's School in South Molton, Devon, and Lecturer of nearby Molland. John Coleridge had three children by his first wife. Samuel was the youngest of ten by the Reverend Mr. Coleridge's second wife, Anne Bowden (1726–1809), probably the daughter of John Bowden, Mayor of South Molton, Devon, in 1726. Coleridge suggests that he "took no pleasure in boyish sports" but instead read "incessantly" and played by himself. After John Coleridge died in 1781, 8-year-old Samuel was sent to Christ's Hospital, a charity school which was founded in the 16th century in Greyfriars, London, where he remained throughout his childhood, studying and writing poetry. At that school Coleridge became friends with Charles Lamb, a schoolmate, and studied the works of Virgil and william Lisle Bowles. In one of a series of autobiographical letters written to Thomas Poole, Coleridge wrote: "At six years old I remember to have read Belisarius, Robinson Crusoe, and Philip Quarll – and then I found the Arabian Nights' Entertainments – one tale of which (the tale of a man who was compelled to seek for a pure virgin) made so deep an impression on me (I had read it in the evening while my mother was mending stockings) that I was haunted by spectres whenever I was in the dark – and I distinctly remember the anxious and fearful eagerness with which I used to watch the window in which the books lay – and whenever the sun lay upon them, I would seize it, carry it by the wall, and bask, and read."

From 1791 until 1794, Coleridge attended Jesus College, Cambridge. In 1792, he won the Browne Gold Medal for an ode that he wrote on the slave trade. In December 1793, he left the college and enlisted in the 15th (The King's) Light Dragoons using the false name "Silas Tomkyn Comberbache", perhaps because of debt or because the girl that he loved, Mary Evans, had rejected him. Afterwards, he was rumoured to have had a bout of severe depression. His brothers arranged for his discharge a few months later under the reason of "insanity" and he was readmitted to Jesus College, though he would never receive a degree from the University.

At Jesus College, Coleridge was introduced to political and theological ideas then considered radical, including those of the poet Robert Southey. Coleridge joined Southey in a plan, soon abandoned, to found a utopian commune-like society, called Pantisocracy, in the wilderness of Pennsylvania. In 1795, the two friends married sisters Sara and Edith Fricker, in St Mary Redcliffe, Bristol, but Coleridge's marriage with Sara proved unhappy. He grew to detest his wife, whom he only married because of social constraints. He eventually separated from her. Coleridge made plans to establish a journal, The Watchman, to be printed every eight days to avoid a weekly newspaper tax. The first issue of the short-lived journal was published in March 1796. It had ceased publication by May of that year.

The years 1797 and 1798, during which he lived in what is now known as Coleridge Cottage, in Nether Stowey, Somerset, were among the most fruitful of Coleridge's life. In 1795, Coleridge met poet william Wordsworth and his sister Dorothy. (Wordsworth, having visited him and being enchanted by the surroundings, rented Alfoxton Park, a little over three miles [5 km] away.) Besides the Rime of The Ancient Mariner, Coleridge composed the symbolic poem Kubla Khan, written—Coleridge himself claimed—as a result of an opium dream, in "a kind of a reverie"; and the first part of the narrative poem Christabel. The writing of Kubla Khan, written about the Mongol Emperor Kublai Khan and his legendary palace at Xanadu, was said to have been interrupted by the arrival of a "Person from Porlock" – an event that has been embellished upon in such varied contexts as science fiction and Nabokov's Lolita. During this period, he also produced his much-praised "conversation poems" This Lime-Tree Bower My Prison, Frost at Midnight, and The Nightingale.

However, Coleridge used these elements in poems such as The Rime of the Ancient Mariner (1798), Christabel and Kubla Khan (published in 1816, but known in manuscript form before then) and certainly influenced other poets and Writers of the time. Poems like these both drew inspiration from and helped to inflame the craze for Gothic romance. Coleridge also made considerable use of Gothic elements in his commercially successful play Remorse.

In 1799, Coleridge and Wordsworths stayed at Thomas Hutchinson's farm on the River Tees at Sockburn, near Darlington.

In 1800, he returned to England and shortly thereafter settled with his family and friends at Keswick in the Lake District of Cumberland to be near Grasmere, where Wordsworth had moved. He was a houseguest of the Wordsworth's for eighteen months, but was a difficult houseguest, as his dependency on laudanum grew and his frequent nightmares would wake the children. He was also a fussy eater, to Dorothy Wordsworth's frustration, who had to cook. For Example, not content with salt, Coleridge sprinkled cayenne pepper on his eggs, which he ate from a teacup. His marital problems, nightmares, illnesses, increased opium dependency, tensions with Wordsworth, and a lack of confidence in his poetic powers fuelled the composition of Dejection: An Ode and an intensification of his philosophical studies.

In 1802, Coleridge took a nine-day walking holiday in the fells of the Lake District. Coleridge is credited with the first recorded descent of Scafell to Mickledore via Broad Stand, although this was more due to his getting lost than a keenness for mountaineering.

In 1804, he travelled to Sicily and Malta, working for a time as Acting Public Secretary of Malta under the Civil Commissioner, Alexander Ball, a task he performed quite successfully. He lived in San Anton Palace in the village of Attard. However, he gave this up and returned to England in 1806. Dorothy Wordsworth was shocked at his condition upon his return. From 1807 to 1808, Coleridge returned to Malta and then travelled in Sicily and Italy, in the hope that leaving Britain's damp climate would improve his health and thus enable him to reduce his consumption of opium. Thomas De Quincey alleges in his Recollections of the Lakes and the Lake Poets that it was during this period that Coleridge became a full-blown opium addict, using the drug as a substitute for the lost vigour and creativity of his youth. It has been suggested, however, that this reflects de Quincey's own experiences more than Coleridge's.

His opium addiction (he was using as much as two quarts of laudanum a week) now began to take over his life: he separated from his wife Sara in 1808, quarrelled with Wordsworth in 1810, lost part of his annuity in 1811, and put himself under the care of Dr. Daniel in 1814. His addiction caused severe constipation, which required regular and humiliating enemas.

In 1809, Coleridge made his second attempt to become a newspaper publisher with the publication of the journal entitled The Friend. It was a weekly publication that, in Coleridge’s typically ambitious style, was written, edited, and published almost entirely single-handedly. Given that Coleridge tended to be highly disorganised and had no head for Business, the publication was probably doomed from the start. Coleridge financed the journal by selling over five hundred subscriptions, over two dozen of which were sold to members of Parliament, but in late 1809, publication was crippled by a financial crisis and Coleridge was obliged to approach "Conversation Sharp", Tom Poole and one or two other wealthy friends for an emergency loan to continue. The Friend was an eclectic publication that drew upon every corner of Coleridge's remarkably diverse knowledge of law, philosophy, morals, politics, history, and literary criticism. Although it was often turgid, rambling, and inaccessible to most readers, it ran for 25 issues and was republished in book form a number of times. Years after its initial publication, The Friend became a highly influential work and its effect was felt on Writers and Philosophers from John Stuart Mill to Ralph Waldo Emerson.

Between 1810 and 1820, Coleridge gave a series of lectures in London and Bristol – those on Shakespeare renewed interest in the Playwright as a model for contemporary Writers. Much of Coleridge's reputation as a literary critic is founded on the lectures that he undertook in the winter of 1810–11, which were sponsored by the Philosophical Institution and given at Scot's Corporation Hall off Fetter Lane, Fleet Street. These lectures were heralded in the prospectus as "A Course of Lectures on Shakespeare and Milton, in Illustration of the Principles of Poetry." Coleridge's ill-health, opium-addiction problems, and somewhat unstable personality meant that all his lectures were plagued with problems of delays and a general irregularity of quality from one lecture to the next. As a result of these factors, Coleridge often failed to prepare anything but the loosest set of notes for his lectures and regularly entered into extremely long digressions which his audiences found difficult to follow. However, it was the lecture on Hamlet given on 2 January 1812 that was considered the best and has influenced Hamlet studies ever since. Before Coleridge, Hamlet was often denigrated and belittled by critics from Voltaire to Dr. Johnson. Coleridge rescued the play's reputation, and his thoughts on it are often still published as supplements to the text.

Between 1814 and 1816, Coleridge lived in Calne, Wiltshire and seemed able to focus on his work and manage his addiction, drafting Biographia Literaria. He rented rooms from local surgeon, Mr Page, on Church Street, just opposite the entrance to the churchyard. A blue plaque marks the property today.

In Gillman's home, Coleridge finished his major prose work, the Biographia Literaria (mostly drafted in 1815, and finished in 1817), a volume composed of 23 chapters of autobiographical notes and dissertations on various subjects, including some incisive literary theory and criticism. He composed a considerable amount of poetry, of variable quality. He published other writings while he was living at the Gillman homes, notably the Lay Sermons of 1816 and 1817, Sibylline Leaves (1817), Hush (1820), Aids to Reflection (1825), and On the Constitution of the Church and State (1830). He also produced essays published shortly after his death, such as Essay on Faith (1838) and Confessions Of An Inquiring Spirit (1840). A number of his followers were central to the Oxford Movement, and his religious writings profoundly shaped Anglicanism in the mid-nineteenth century.

In April 1816, Coleridge, with his addiction worsening, his spirits depressed, and his family alienated, took residence in the Highgate homes, then just north of London, of the physician James Gillman, first at South Grove and later at the nearby 3 The Grove. It is unclear whether his growing use of opium (and the Brandy in which it was dissolved) was a symptom or a cause of his growing depression. Gillman was partially successful in controlling the poet's addiction. Coleridge remained in Highgate for the rest of his life, and the house became a place of literary pilgrimage for Writers including Carlyle and Emerson.

In addition to his poetry, Coleridge also wrote influential pieces of literary criticism including Biographia Literaria, a collection of his thoughts and opinions on literature which he published in 1817. The work delivered both biographical explanations of the author's life as well as his impressions on literature. The collection also contained an analysis of a broad range of philosophical principles of literature ranging from Aristotle to Immanuel Kant and Schelling and applied them to the poetry of peers such as william Wordsworth. Coleridge's explanation of metaphysical principles were popular topics of discourse in academic communities throughout the 19th and 20th centuries, and T.S. Eliot stated that he believed that Coleridge was "perhaps the greatest of English critics, and in a sense the last." Eliot suggests that Coleridge displayed "natural abilities" far greater than his contemporaries, dissecting literature and applying philosophical principles of metaphysics in a way that brought the subject of his criticisms away from the text and into a world of logical analysis that mixed logical analysis and emotion. However, Eliot also criticises Coleridge for allowing his emotion to play a role in the metaphysical process, believing that critics should not have emotions that are not provoked by the work being studied. Hugh Kenner in Historical Fictions, discusses Norman Fruman's Coleridge, the Damaged Archangel and suggests that the term "criticism" is too often applied to Biographia Literaria, which both he and Fruman describe as having failed to explain or help the reader understand works of art. To Kenner, Coleridge's attempt to discuss complex philosophical concepts without describing the rational process behind them displays a lack of critical thinking that makes the volume more of a biography than a work of criticism.

Coleridge died in Highgate, London on 25 July 1834 as a result of heart failure compounded by an unknown lung disorder, possibly linked to his use of opium. Coleridge had spent 18 years under the roof of the Gillman family, who built an addition onto their home to accommodate the poet.

The eight of Coleridge's poems listed above are now often discussed as a group entitled "Conversation poems". The term itself was coined in 1928 by George McLean Harper, who borrowed the subtitle of The Nightingale: A Conversation Poem (1798) to describe the seven other poems as well. The poems are considered by many critics to be among Coleridge's finest verses; thus Harold Bloom has written, "With Dejection, The Ancient Mariner, and Kubla Khan, Frost at Midnight shows Coleridge at his most impressive." They are also among his most influential poems, as discussed further below.

Coleridge is buried in the aisle of St. Michael's Parish Church in Highgate, London. He was originally buried at Old Highgate Chapel but was re-interred in St. Michael's in 1961. Coleridge could see the red door of the then new church from his last residence across the green, where he lived with a Doctor he'd hoped might cure him (in a house owned today by Kate Moss). When it was discovered Coleridge’s vault had become derelict, the coffins – Coleridge's and those of his wife, daughter, son-in-law, and grandson – were moved to St Michael’s after an international fundraising appeal.

In 1965, M. H. Abrams wrote a broad description that applies to the Conversation poems: "The speaker begins with a description of the landscape; an aspect or change of aspect in the landscape evokes a varied by integral process of memory, thought, anticipation, and feeling which remains closely intervolved with the outer scene. In the course of this meditation the lyric speaker achieves an insight, faces up to a tragic loss, comes to a moral decision, or resolves an emotional Problem. Often the poem rounds itself to end where it began, at the outer scene, but with an altered mood and deepened understanding which is the result of the intervening meditation." In fact, Abrams was describing both the Conversation poems and later poems influenced by them. Abrams' essay has been called a "touchstone of literary criticism". As Paul Magnuson described it in 2002, "Abrams credited Coleridge with originating what Abrams called the 'greater Romantic lyric', a genre that began with Coleridge's 'Conversation' poems, and included Wordsworth's Tintern Abbey, Shelley's Stanzas Written in Dejection and Keats's Ode to a Nightingale, and was a major influence on more modern lyrics by Matthew Arnold, Walt Whitman, Wallace Stevens, and W. H. Auden."

A current standard edition is The Collected Works of Samuel Taylor Coleridge, edited by Kathleen Coburn and many others from 1969 to 2002. This collection appeared across 16 volumes as Bollingen Series 75, published variously by Princeton University Press and Routledge & Kegan Paul. The set is broken down as follows into further parts, resulting in a total of 34 separate printed volumes :

Coleridge also worked extensively on the various manuscripts which form his "Opus Maximum", a work which was in part intended as a post-Kantian work of philosophical synthesis. The work was never published in his lifetime, and has frequently been seen as evidence for his tendency to conceive grand projects which he then had difficulty in carrying through to completion. But while he frequently berated himself for his "indolence", the long list of his published works calls this myth into some question. Critics are divided on whether the "Opus Maximum", first published in 2002, successfully resolved the philosophical issues he had been exploring for most of his adult life.

Harper himself considered that the eight poems represented a form of blank verse that is "...more fluent and easy than Milton's, or any that had been written since Milton". In 2006 Robert Koelzer wrote about another aspect of this apparent "easiness", noting that Conversation poems such as "... Coleridge's The Eolian Harp and The Nightingale maintain a middle register of speech, employing an idiomatic language that is capable of being construed as un-symbolic and un-musical: language that lets itself be taken as 'merely talk' rather than rapturous 'song'."

Coleridge wrote reviews of Ann Radcliffe's books and The Mad Monk, among others. He comments in his reviews: "Situations of torment, and images of naked horror, are easily conceived; and a Writer in whose works they abound, deserves our gratitude almost equally with him who should drag us by way of sport through a military hospital, or force us to sit at the dissecting-table of a natural Philosopher. To trace the nice boundaries, beyond which terror and sympathy are deserted by the pleasurable emotions, – to reach those limits, yet never to pass them, hic labor, hic opus est." and "The horrible and the preternatural have usually seized on the popular taste, at the rise and decline of literature. Most powerful stimulants, they can never be required except by the torpor of an unawakened, or the languor of an exhausted, appetite... We trust, however, that satiety will banish what good sense should have prevented; and that, wearied with fiends, incomprehensible characters, with shrieks, murders, and subterraneous dungeons, the public will learn, by the multitude of the manufacturers, with how little expense of thought or imagination this species of composition is manufactured."

In Biographia Literaria and his poetry, symbols are not merely "objective correlatives" to Coleridge, but instruments for making the universe and personal experience intelligible and spiritually covalent. To Coleridge, the "cinque spotted spider," making its way upstream "by fits and starts," [Biographia Literaria] is not merely a comment on the intermittent nature of creativity, imagination, or spiritual progress, but the journey and destination of his life. The spider's five legs represent the central Problem that Coleridge lived to resolve, the conflict between Aristotelian logic and Christian philosophy. Two legs of the spider represent the "me-not me" of thesis and antithesis, the idea that a thing cannot be itself and its opposite simultaneously, the basis of the clockwork Newtonian world view that Coleridge rejected. The remaining three legs—exothesis, mesothesis and synthesis or the Holy trinity—represent the idea that things can diverge without being contradictory. Taken together, the five legs—with synthesis in the center, form the Holy Cross of Ramist logic. The cinque-spotted spider is Coleridge's emblem of holism, the quest and substance of Coleridge's thought and spiritual life.

Coleridge was also a profound political thinker. While he began his life as a political radical, and an enthusiast for the French Revolution; over the years Coleridge developed a more conservative view of society, somewhat in the manner of Burke. Although seen as cowardly treachery by the next generation of Romantic poets, Coleridge’s later thought became a fruitful source for the evolving radicalism of J. S. Mill. Mill found three aspects of Coleridge’s thought especially illuminating: