Few details are known of Gower's early life. He was probably born to an affluent family from Kent (Southeast England), and may have been a landowner. It is thought that he practised law in or around London.

While in London, he became closely associated with the nobility of his day. He was apparently personally acquainted with Richard II: in the prologue of the first edition of the Confessio Amantis, he tells how the king, chancing to meet him on the Thames (probably circa 1385), invited him aboard the royal barge, and that their conversation then resulted in a commission for the work that would become the Confessio Amantis. Later in life his allegiance switched to the side of the future Henry IV, to whom later editions of the Confessio Amantis were dedicated.

Gower's friendship with Chaucer is also well documented. When Chaucer was sent as a diplomat to Italy in 1378, Gower was one of the men to whom he gave power of attorney over his affairs in England. The two poets also paid one another compliments in their verse: Chaucer dedicated his Troilus and Criseyde in part to "moral Gower", and Gower reciprocated by placing a speech in praise of Chaucer in the mouth of Venus at the end of the Confessio Amantis.

Towards the end of his life, he took up residence in rooms provided by the Priory of St Mary Overie (now Southwark Cathedral). In 1398, while living here, he married, probably for the second time: his wife, Agnes Groundolf, was to survive him. In his last years, and possibly as early as 1400, he became blind.

After his death in 1408, Gower was interred in an ostentatious tomb in the Priory church (now Southwark Cathedral), which remains today.

Gower's verse is by turns religious, political, historical, and moral—though he has been narrowly defined as "moral Gower" ever since Chaucer graced him with the epithet. His primary mode is allegory, although he shies away from sustained abstractions in favour of the plain style of the raconteur.

His earliest works were probably ballades in Anglo-Norman French, some of which may have later been included in his work the Cinkante Ballades. The first work which has survived is in the same language, however: it is the Speculum Meditantis, also known by the French title Mirour de l'Omme, a poem of just under 30,000 lines, containing a dense exposition of religion and morality.

Gower's second major work, the Vox Clamantis, was written in Latin: it takes as its subject the state of England, and incorporates commentary on the Peasants' Revolt that occurred during the composition of the poem. Gower takes the side of the aristocracy, and appears to have admired the techniques Richard II used to suppress the revolt.

His third work is the Confessio Amantis, a 30,000-line poem in octosyllabic English couplets, which makes use of the structure of a Christian confession (presented allegorically as a confession of sins against Love) as a narrative frame within which a multitude of individual tales are told. Like his previous works, the theme is very much morality, even where the stories themselves have a tendency to describe rather immoral behaviour. One scholar asserts that Confessio Amantis "almost exclusively" made Gower's "poetic reputation."

In later years Gower wrote a number of minor works in all three languages: the Cinkante Ballades, a series of French ballades on romantic subjects, and several poems addressed to the new Henry IV—in return for which he was granted a pension, in the form of an annual allowance of wine.

Gower's poetry has had a mixed critical reception. In the 15th century, he was generally regarded alongside Chaucer as the father of English poetry. Over the years, however, his reputation declined, largely on account of a perceived didacticism and dullness. During the 20th century he has received more recognition, notably by C. S. Lewis in The Allegory of Love (1936). However, he has not obtained the same following or critical acceptance as other major poets of the period.