Monteverdi was baptised in the church of SS Nazaro e Celso, Cremona, on 15 May 1567. The register records his name as "Claudio Zuan Antonio" the son of "Messer Baldasar Mondeverdo". He was the first child of the apothecary Baldassare Monteverdi and his first wife Maddalena (née Zignani); they had married early the previous year. Claudio's brother Giulio Cesare Monteverdi (b. 1573) was also to become a musician; there were two other brothers and two sisters from Baldassare's marriage to Maddalena and his subsequent marriage in 1576 or 1577. Cremona lay under the jurisdiction of Milan, a Spanish possession, so that Monteverdi was technically born a Spanish subject. Cremona was close to the border of the Republic of Venice, and not far from the lands controlled by Mantua, in both of which states Monteverdi was later to establish his career.

Ingegneri, Monteverdi's first tutor, was a master of the musica reservata vocal style, which involved the use of chromatic progressions and word-painting; Monteverdi's early compositions were grounded in this style. Ingegneri was a traditional Renaissance Composer, "something of an anachronism" according to Arnold, but Monteverdi also studied the work of more "modern" composers such as Luca Marenzio, Luzzasco Luzzaschi, and a little later, Giaches de Wert, from whom he would learn the art of expressing passion. He was a precocious and productive student, as indicated by his youthful publications of 1582–83. Paul Ringer writes that "these teenaged efforts reveal palpable ambition matched with a convincing mastery of contemporary style", but at this stage they display their creator's competence rather than any striking originality. Geoffrey Chew classifies them as "not in the most modern vein for the period", acceptable but out-of-date. Chew rates the Canzonette collection of 1584 much more highly than the earlier juvenilia: "These brief three-voice pieces draw on the airy, modern style of the villanellas of Marenzio, [drawing on] a substantial vocabulary of text-related madrigalisms".

The Vespro della Beata Vergine, Monteverdi's first published sacred music since the Madrigali spirituali of 1583, consists of 14 components: an introductory versicle and response, five psalms interspersed with five "sacred concertos" (Monteverdi's term), a hymn, and two Magnificat settings. Collectively these pieces fulfil the requirements for a Vespers Service on any feast day of the Virgin. Monteverdi employs many musical styles; the more traditional features, such as cantus firmus, falsobordone and Venetian canzone, are mixed with the latest madrigal style, including echo effects and chains of dissonances. Some of the musical features used are reminiscent of L'Orfeo, written slightly earlier for similar instrumental and vocal forces.

The canzonetta form was much used by composers of the day as a technical exercise, and is a prominent element in Monteverdi's first book of madrigals published in 1587. In this book, the playful, pastoral settings again reflect the style of Marenzio, while Luzzaschi's influence is evident in Monteverdi's use of dissonance. The second book (1590) begins with a setting modelled on Marenzio of a modern verse, Torquato Tasso's "Non si levav' ancor", and concludes with a text from 50 years earlier: Pietro Bembo's "Cantai un tempo". Monteverdi set the latter to music in an archaic style reminiscent of the long-dead Cipriano de Rore. Between them is "Ecco mormorar l'onde", strongly influenced by de Wert and hailed by Chew as the great masterpiece of the second book.

As the 1590s progressed, Monteverdi moved closer towards the form that he would identify in due course as the seconda pratica. Claude V. Palisca quotes the madrigal Ohimè, se tanto amate, published in the fourth book but written before 1600 – it is among the works attacked by Artusi – as a typical Example of the composer's developing powers of invention. In this madrigal Monteverdi again departs from the established practice in the use of dissonance, by means of a vocal ornament Palisca describes as échappé. Monteverdi's daring use of this device is, says Palisca, "like a forbidden pleasure". In this and in other settings the poet's images were supreme, even at the expense of musical consistency.

Monteverdi's first fifteen years of Service in Mantua are bracketed by his publications of the third book of Madrigals in 1592 and the fourth and fifth books in 1603 and 1605. Between 1592 and 1603 he made minor contributions to other anthologies. How much he composed in this period is a matter of conjecture; his many duties in the Mantuan court may have limited his opportunities, but several of the madrigals that he published in the fourth and fifth books were written and performed during the 1590s, some figuring prominently in the Artusi controversy.

When Wert died in 1596, his post was given to Benedetto Pallavicino, but Monteverdi was clearly highly regarded by Vincenzo and accompanied him on his military campaigns in Hungary (1595) and also on a visit to Flanders in 1599. Here at the town of Spa he is reported by his brother Giulio Cesare as encountering, and bringing back to Italy, the canto alla francese. (The meaning of this, literally "song in the French style", is debatable, but may refer to the French-influenced poetry of Gabriello Chiabrera, some of which was set by Monteverdi in his Scherzi musicali, and which departs from the traditional Italian style of lines of 9 or 11 syllables). Monteverdi may possibly have been a member of Vincenzo's entourage at Florence in 1600 for the marriage of Maria de' Medici and Henry IV of France, at which celebrations Jacopo Peri's opera Euridice (the earliest surviving opera) was premiered. On the death of Pallavicino in 1601 Monteverdi was confirmed as the new maestro di capella.

Duke Vincenzo was keen to establish his court as a musical centre, and sought to recruit leading Musicians. When Monteverdi arrived in Mantua, the maestro di capella at the court was the Flemish musician Giaches de Wert. Other notable Musicians at the court during this period included the Composer and Violinist Salomone Rossi, Rossi's sister the singer Madama Europa, and the tenor Francesco Rasi. Monteverdi married the court singer Claudia de Cattaneis in 1599; they were to have three children, two sons (Francesco, b. 1601 and Massimiliano, b. 1604), and a daughter who died soon after birth in 1603. Monteverdi's brother Giulio Cesare joined the court Musicians in 1602.

At the turn of the 17th century, Monteverdi found himself the target of musical controversy. The influential Bolognese theorist Giovanni Maria Artusi attacked Monteverdi's music (without naming the composer) in his work L'Artusi, overo Delle imperfettioni della moderna musica (Artusi, or On the imperfections of modern music) of 1600, followed by a sequel in 1603. Artusi cited extracts from Monteverdi's works not yet published (they later formed parts of his fourth and fifth books of madrigals of 1603 and 1605), condemning their use of harmony and their innovations in use of musical modes, compared to orthodox polyphonic practice of the sixteenth century. Artusi attempted to correspond with Monteverdi on these issues; the Composer refused to respond, but found a champion in a pseudonymous supporter, "L'Ottuso Academico" ("The Obtuse Academic"). Eventually Monteverdi replied in the preface to the fifth book of madrigals that his duties at court prevented him from a detailed reply; but in a note to "the studious reader", he claimed that he would shortly publish a response, Seconda Pratica, overo Perfettione della Moderna Musica (The Second Style, or Perfection of Modern Music). This work never appeared, but a later publication by Claudio's brother Giulio Cesare made it clear that the seconda pratica which Monteverdi defended was not seen by him as radical change or his own invention, but was an evolution from previous styles (prima pratica) which was complementary to them.

This debate seems in any case to have raised the composer's profile, leading to reprints of his earlier books of madrigals. Some of his madrigals were published in Copenhagen in 1605 and 1606, and the poet Tommaso Stigliani published a eulogy of him in his 1605 poem "O sirene de' fiumi". The Composer of madrigal comedies and theorist Adriano Banchieri wrote in 1609: "I must not neglect to mention the most noble of composers, Monteverdi ... his expressive qualities are truly deserving of the highest commendation, and we find in them countless examples of matchless declamation ... enhanced by comparable harmonies." The modern music Historian Massimo Ossi has placed the Artusi issue in the context of Monteverdi's artistic development: "If the controversy seems to define Monteverdi's historical position, it also seems to have been about stylistic developments that by 1600 Monteverdi had already outgrown".

In 1606 Vincenzo's heir Francesco commissioned from Monteverdi the opera L'Orfeo, to a libretto by Alessandro Striggio, for the Carnival season of 1607. It was given two performances in February and March 1607; the Singers included, in the title role, Rasi, who had sung in the first performance of Euridice witnessed by Vincenzo in 1600. This was followed in 1608 by the opera L'Arianna (libretto by Ottavio Rinuccini), intended for the celebration of the marriage of Francesco to Margherita of Savoy. All the music for this opera is lost apart from Ariadne's Lament, which became extremely popular. To this period also belongs the ballet entertainment Il ballo delle ingrate.

The last years of Monteverdi's life were much occupied with opera for the Venetian stage. Richard Taruskin, in his Oxford History of Western Music, gives his chapter on this topic the title "Opera from Monteverdi to Monteverdi." This wording, originally proposed humorously by the Italian music Historian Nino Pirrotta, is interpreted seriously by Taruskin as indicating that Monteverdi is significantly responsible for the transformation of the opera genre from a private entertainment of the nobility (as with Orfeo in 1607), to what became a major commercial genre, as exemplified by his opera L'incoronazione di Poppea (1643). His two surviving operatic works of this period, Il ritorno d'Ulisse in patria and L'incoronazione are held by Arnold to be the first "modern" operas; Il ritorno is the first Venetian opera to depart from what Ellen Rosand terms "the mythological pastoral". However, David Johnson in The North American Review warns audiences not to expect immediate affinity with Mozart, Verdi or Puccini: "You have to submit yourself to a much slower pace, to a much more chaste conception of melody, to a vocal style that is at first merely like dry declamation and only on repeated hearings begins to assume an extraordinary eloquence."

It is difficult to gauge when many of the pieces were composed, although the ballet Mascherata dell' ingrate that ends the book dates back to 1608 and the celebration of the Gonzaga-Savoy marriage. The Combattimento di Tancredi e Clorinda, centrepiece of the "war" settings, had been written and performed in Venice in 1624; on its publication in the eighth book, Monteverdi explicitly linked it to his concept of concitato genera (otherwise stile concitato – "aroused style") that would "fittingly imitate the utterance and the accents of a brave man who is engaged in warfare", and implied that since he had originated this style, others had begun to copy it. The work employed for the first time instructions for the use of pizzicato string chords, and also evocations of fanfares and other sounds of combat.

Much of Monteverdi's output, including many stage works, has been lost. His surviving music includes nine books of madrigals, large-scale sacred works such as his Vespro della Beata Vergine (Vespers) of 1610, and three complete operas. His opera L'Orfeo (1607) is the earliest of the genre still widely performed; towards the end of his life he wrote works for the commercial theatre in Venice, including Il ritorno d'Ulisse in patria and L'incoronazione di Poppea.

Duke Vincenzo died on 18 February 1612. When Francesco succeeded him, court intrigues and cost-cutting let to the dismissal of Monteverdi and his brother Giulio Cesare, who both returned, almost penniless, to Cremona. Despite Francesco's own death from smallpox in December 1612, Monteverdi was unable to return to favour with his successor, his brother Cardinal Ferdinando Gonzaga. In 1613, following the death of Giulio Cesare Martinengo, Monteverdi auditioned for his post as maestro at the basilica of San Marco in Venice, for which he submitted music for a Mass. He was appointed in August 1613, and given 50 ducats for his expenses (of which he was robbed, together with his other belongings, by highwaymen at Sanguinetto on his return to Cremona).

During his years in Venice Monteverdi published his sixth (1614), seventh (1619) and eighth (1638) books of madrigals. The sixth book consists of works written before the composer's departure from Mantua. Hans Redlich sees it as a transitional work, containing Monteverdi's last madrigal compositions in the manner of the prima pratica, together with music which is typical of the new style of expression which Monteverdi had displayed in the dramatic works of 1607–08. The central theme of the collection is loss; the best-known work is the five-voice version of Lamento d'Arianna, which, says Massimo Ossi, gives "an object lesson in the close relationship between monodic recitative and counterpoint". The book contains Monteverdi's first settings of verses by Giambattista Marino, and two settings of Petrarch which Ossi considers the most extraordinary pieces in the volume, providing some "stunning musical moments".

Martinengo had been ill for some time before his death and had left the music of San Marco in a fragile state. The choir had been neglected and the administration overlooked. When Monteverdi arrived to take up his post, his principal responsibility was to recruit, train, discipline and manage the Musicians of San Marco (the capella), who amounted to about 30 Singers and six instrumentalists; the numbers could be increased for major events. Among the recruits to the choir was Francesco Cavalli, who joined in 1616 at the age of 14; he was to remain connected with San Marco throughout his life, and was to develop a close association with Monteverdi. Monteverdi also sought to expand the repertory, including not only the traditional a cappella repertoire of Roman and Flemish composers, but also examples of the modern style which he favoured, including the use of continuo and other instruments. Apart from this he was of course expected to compose music for all the major feasts of the church. This included a new mass each year for Holy Cross Day and Christmas Eve, cantatas in honour of the Venetian Doge, and numerous other works (many of which are lost). Monteverdi was also free to obtain income by providing music for other Venetian churches and for other patrons, and was frequently commissioned to provide music for state banquets. The Procurators of San Marco, to whom Monteverdi was directly responsible, showed their satisfaction with his work in 1616 by raising his annual salary from 300 ducats to 400.

Monteverdi also received commissions from other Italian states and from their communities in Venice. These included, for the Milanese community in 1620, music for the Feast of St. Charles Borromeo, and for the Florentine community a Requiem Mass for Cosimo II de' Medici (1621). Monteverdi acted on behalf of Paolo Giordano II, Duke of Bracciano, to arrange publication of works by the Cremona musician Francesco Petratti. Among Monteverdi's private Venetian patrons was the nobleman Girolamo Mocenigo, at whose home was premiered in 1624 the dramatic entertainment Il combattimento di Tancredi e Clorinda based on an episode from Torquato Tasso's La Gerusalemme liberata. In 1627 Monteverdi received a major commission from Odoardo Farnese, Duke of Parma, for a series of works, and gained leave from the Procurators to spend time there during 1627 and 1628.

There is a consensus among music historians that a period extending from the mid-15th century to around 1625, characterised in Lewis Lockwood's phrase by "substantial unity of outlook and language", should be identified as the period of "Renaissance music". Musical literature has also defined the succeeding period (covering music from approximately 1580 to 1750) as the era of "Baroque music". It is in the late-16th to early-17th-century overlap of these periods that much of Monteverdi's creativity flourished; he stands as a transitional figure between the Renaissance and the Baroque.

The German Composer Heinrich Schütz, who had studied in Venice under Giovanni Gabrieli shortly before Monteverdi's arrival there, possessed a copy of Il combattimento and himself took up elements of the "stile concitato". On his second visit to Venice in 1628–1629, Arnold believes, Schütz absorbed the concepts of basso continuo and expressiveness of word-setting, but he opines that Schütz was more directly influenced by the style of the younger generation of Venetian composers, including Grandi and Giovanni Rovetta (the eventual successor to Monteverdi at San Marco). Schütz published a first book of Symphonia sacrae, settings of biblical texts in the style of seconda pratica, in Venice in 1629. Es steh Gott auf, from his Symphoniae sacrae II, published in Dresden in 1647, contains specific quotations from Monteverdi.

Monteverdi retained emotional and political attachments to the Mantuan court and wrote for it, or undertook to write, large amounts of stage music including at least four operas. The ballet Tirsi e Clori survives through its inclusion in the seventh book, but the rest of the Mantuan dramatic music is lost. Many of the missing manuscripts may have disappeared in the wars that overcame Mantua in 1630. The most significant aspect of their loss, according to Carter, is the extent to which they might have provided musical links between Monteverdi's early Mantuan operas and those he wrote in Venice after 1638: "Without these links ... it is hard to a produce a coherent account of his development as a Composer for the stage". Likewise, Janet Beat regrets that the 30-year gap hampers the study of how opera orchestration developed during those critical early years.

Apart from the madrigal books, Monteverdi's only published collection during this period was the volume of Scherzi musicale in 1632. For unknown reasons, the composer's name does not appear on the inscription, the dedication being signed by the Venetian printer Bartolemeo Magni; Carter surmises that the recently ordained Monteverdi may have wished to keep his distance from this secular collection. It mixes strophic continuo songs for solo voice with more complex works which employ continuous variation over repeated bass patterns. Chew selects the chaconne for two tenors, Zefiro torna e di soavi accenti, as the outstanding item in the collection: "[T]he greater part of this piece consists of repetitions of a bass pattern which ensures tonal unity of a simple kind, owing to its being framed as a simple cadence in a G major tonal type: over these repetitions, inventive variations unfold in virtuoso passage-work".

Monteverdi is lauded by modern critics as "the most significant Composer in late Renaissance and early Baroque Italy"; "one of the principal composers in the history of Western music"; and, routinely, as the first great opera Composer. These assessments reflect a contemporary perspective, since his music was largely unknown to the composers that followed him for three centuries after his death. It is, as Redlich and others have pointed out, the composers of the late 20th and 21st century that have identified with Monteverdi and sought to make his music a basis for their own. Possibly, as Chew suggests, they are attracted by Monteverdi's reputation as "a Modern, a breaker of rules, against the Ancients, those who deferred to ancient authority" – although the Composer was, essentially, a pragmatist, "showing what can only be described as an opportunistic and eclectic willingness to use whatever lay to hand for the purpose". In a letter dated 16 October 1633 Monteverdi appears to endorse the view of himself as a "modern": "I would rather be moderately praised for the new style than greatly praised for the ordinary". However, Chew, in his final summation, sees the Composer historically as facing both ways, willing to use modern techniques but while at the same time protective of his status as a competent Composer in the stile antico. Thus, says Chew, "his achievement was both retrospective and progressive". Monteverdi represents the late Renaissance era while simultaneously summing up much of the early Baroque. "And in one respect in particular, his achievement was enduring: the effective projection of human emotions in music, in a way adequate for theatre as well as for chamber music."

The eighth book, subtitled Madrigali guerrieri, et amorosi ... ("Madrigals of war and love") is structured in two symmetrical halves, one for "war" and one for "love". Each half begins with a six-voice setting, followed by an equally large-scale Petrarch setting, then a series of duets mainly for tenor voices, and concludes with a theatrical number and a final ballet. The "war" half contains several items written as tributes to the Emperor Ferdinand III, who had succeeded to the Habsburg throne in 1637. Many of Monteverdi's familiar poets – Strozzi, Rinuccini, Tasso, Marino, Guarini – are represented in the settings.

Monteverdi's contribution to opera at this period is notable. He revised his earlier opera L'Arianna in 1640 and wrote three new works for the commercial stage, Il ritorno d'Ulisse in patria (The Return of Ulysses to his Homeland, 1640, first performed in Bologna with Venetian singers), Le nozze d'Enea e Lavinia (The Marriage of Aeneas and Lavinia, 1641, music now lost), and L'incoronazione di Poppea (The Coronation of Poppea, 1643). The introduction to the printed scenario of Le nozze d'Enea, by an unknown author, acknowledges that Monteverdi is to be credited for the rebirth of theatrical music and that "he will be sighed for in later ages, for his compositions will surely outlive the ravages of time."

The Selva morale e spirituale of 1641, and the posthumous Messa et salmi published in 1650 (which was edited by Cavalli), are selections of the sacred music that Monteverdi wrote for San Marco during his 30-year tenure – much else was likely written but not published. The Selva morale volume opens with a series of madrigal settings on moral texts, dwelling on themes such as "the transitory nature of love, earthly rank and achievement, even existence itself". They are followed by a Mass in conservative style (stile antico), the high point of which is an extended seven-voice "Gloria". Scholars believe that this might have been written to celebrate the end of the 1631 plague. The rest of the volume is made up of numerous psalm settings, two Magnificats and three Salve Reginas. The Messa et salmi volume includes a stile antico Mass for four voices, a polyphonic setting of the psalm Laetatus Sum, and a version of the Litany of Lareto that Monteverdi had originally published in 1620.

In his last surviving letter (20 August 1643), Monteverdi, already ill, was still hoping for the settlement of the long-disputed pension from Mantua, and asked the Doge of Venice to intervene on his behalf. He died in Venice on 29 November 1643, after paying a brief visit to Cremona, and is buried in the Church of the Frari. He was survived by his sons; Masimilliano died in 1661, Francesco after 1677.

After the 1650s, Monteverdi's name quickly disappears from contemporary accounts, his music generally forgotten except for the Lamento, prototype of a genre that would endure well into the 18th century.

In his lifetime Monteverdi enjoyed considerable status among Musicians and the public. This is evidenced by the scale of his funeral rites: "[W]ith truly royal pomp a catafalque was erected in the Chiesa de Padrini Minori de Frari, decorated all in mourning, but surrounded with so many candles that the church resembled a night sky luminous with stars". This glorification was transitory; Carter writes that in Monteverdi's day, music rarely survived beyond the circumstances of its initial performance and was quickly forgotten along with its creator. In this regard Monteverdi fared better than most. His operatic works were revived in several cities in the decade following his death; according to Severo Bonini writing in 1651, every musical household in Italy possessed a copy of the Lamento d'Arianna.

Interest in Monteverdi revived in the late 18th and early 19th centuries among music scholars in Germany and Italy, although he was still regarded as essentially a historical curiosity. Wider interest in the music itself began in 1881, when Robert Eitner published a shortened version of the Orfeo score. Around this time Kurt Vogel scored the madrigals from the original manuscripts, but more critical interest was shown in the operas, following the discovery of the L'incoronazione manuscript in 1888 and that of Il ritorno in 1904. Largely through the efforts of Vincent d'Indy, all three operas were staged in one form or other, during the first quarter of the 20th century: L'Orfeo in May 1911, L'incoronazione in February 1913 and Il ritorno in May 1925.

The Italian nationalist poet Gabriele D'Annunzio lauded Monteverdi and in his novel Il fuoco (1900) wrote of "il divino Claudio ... what a heroic soul, purely Italian in its essence!" His vision of Monteverdi as the true founder of Italian musical lyricism was adopted by Musicians who worked with the regime of Benito Mussolini (1922–1945), including Francesco Malipiero, Luigi Dallapiccola, and Mario Labroca, who contrasted Monteverdi with the decadence of the music of Richard Strauss, Claude Debussy and Igor Stravinsky.

In the years after the Second World War the operas began to be performed in the major opera houses, and eventually were established in the general repertory. The resuscitation of Monteverdi's sacred music took longer; he did not benefit from the Catholic Church's 19th-century revival of Renaissance music in the way that Palestrina did, perhaps, as Carter suggests, because Monteverdi was viewed chiefly as a secular Composer. It was not until 1932 that the 1610 Vespers were published in a modern edition, followed by Redlich's revision two years later. Modern editions of the Selva morales and Missa e Salmi volumes were published respectively in 1940 and 1942.

The revival of public interest in Monteverdi's music gathered pace in the second half of the 20th century, reaching full spate in the general early-music revival of the 1970s, during which time the emphasis turned increasingly towards "authentic" performance using historical instruments. The magazine Gramophone notes over 30 recordings of the Vespers between 1976 and 2011, and 27 of Il combattimento di Tancredo e Clorinda between 1971 and 2013. Monteverdi's surviving operas are today regularly performed; the website Operabase notes 555 performances of the operas in 149 productions worldwide in the seasons 2011–2016, ranking Monteverdi at 30th position for all composers, and at 8th ranking for Italian opera composers. In 1985 Manfred H. Stattkus published an index to Monteverdi's works, the Stattkus-Verzeichnis, (revised in 2006) giving each composition an "SV" number, to be used for cataloguing and references.

Rinuccini's full libretto, which has survived, was set in modern times by Alexander Goehr (Arianna, 1995), including a version of Monteverdi's Lament.

While Monteverdi had looked backwards in the sixth book, he moved forward in the seventh book from the traditional concept of the madrigal, and from monody, in favour of chamber duets. There are exceptions, such the two solo lettere amorose (love letters) "Se i languidi miei sguardi" and "Se pur destina e vole", written to be performed genere rapresentativo – acted as well as sung. Of the duets which are the main features of the volume, Chew highlights "Ohimé, dov'è il mio ben, dov'è il mio core", a romanesca in which two high voices express dissonances above a repetitive bass pattern. The book also contains large-scale ensemble works, and the ballet Tirsi e Clori. This was the height of Monteverdi's "Marino period"; six of the pieces in the book are settings of the poet's verses. As Carter puts it, Monteverdi "embraced Marino's madrigalian kisses and love-bites with ... the enthusiasm typical of the period". Some commentators have opined that the Composer should have had better poetic taste.

Throughout the opera Monteverdi makes innovative use of polyphony, extending the rules beyond the conventions which composers normally observed in fidelity to Palestrina. He combines elements of the traditional 16th-century madrigal with the new monodic style where the text dominates the music and sinfonias and instrumental ritornellos illustrate the action.

The critic Andrew Clements describes the eighth book as "a statement of artistic principles and compositional authority", in which Monteverdi "shaped and expanded the madrigal form to accommodate what he wanted to do ... the pieces collected in Book Eight make up a treasury of what music in the first half the 17th century could possibly express."