He was born at Clive, Shropshire near Shrewsbury, where his family was settled on a moderate estate of about £600 a year. Like John Vanbrugh, Wycherley spent some years of his adolescence in France, where he was sent, at fifteen, to be educated in the heart of the "precious" circle on the banks of the Charente. Wycherley's friend, Major Pack, said that he there "improved, with the greatest refinements", the "extraordinary talents" for which he was "obliged to nature".

While in France, Wycherley converted to Roman Catholicism. He returned to England shortly before the restoration of King Charles II, and lived at Queen's College, Oxford where Thomas Barlow was provost. Under Barlow's influence, Wycherley returned to the Church of England. Wycherley only lived in the provost's lodgings; he does not seem to have matriculated or taken a degree.

Thomas Macaulay hints that Wycherley's turning back to Roman Catholicism once more had something to do with the patronage and unwonted liberality of the future James II. As a professional fine gentleman, at a period when, as the genial Major Pack says, "the amours of Britain would furnish as diverting memoirs, if well related, as those of France published by Rabutin, or those of Nero's court writ by Petronius", Wycherley was obliged to be a loose liver. However, his nickname of "Manly Wycherley" seems to have been earned by his straightforward attitude to life.

Wycherley left Oxford and took up residence at the Inner Temple, but gave little attention to the study of law. Pleasure and the stage were his only interests. His play, Love in a Wood, was produced early in 1671 at the Theatre Royal, Drury Lane. It was published the next year. Though Wycherley boasted of having written the play at the age of nineteen, before going to Oxford, this is probably untrue. Macaulay points to the allusions in the play to gentlemen's periwigs, to guineas, to the vests which Charles ordered to be worn at court, to the Great Fire of London, etc, as showing that the comedy could not have been written the year before the author went to Oxford. However, even if the play had been written in that year, and delayed in its production till 1672, it is exactly this kind of allusion to recent events which any dramatist with an eye to freshness of colour would be certain to weave into his dialogue.

That the writer of a play far more daring than Etheredge's She Would if She Could — and far more brilliant too — should at once become the talk of the court was inevitable; equally inevitable was it that the author of the song at the end of the first act, in praise of harlots and their offspring, should attract the attention of the king's mistress, Barbara Villiers, Duchess of Cleveland. Possibly Wycherley intended this famous song as a glorification of Her Grace and her profession, for he seems to have been more delighted than surprised when, as he passed in his coach through Pall Mall, he heard her address him from her coach window as a "rascal" and a "villain", and the son of a woman such as that mentioned in the song. His answer was perfect: "Madam, you have been pleased to bestow a title on me which belongs only to the fortunate." Seeing that she received the compliment in the spirit in which it was meant, he lost no time in calling upon her, and was from that moment the recipient of those "favours" to which he alludes with pride in the dedication of the play to her. Voltaire's story (in his Letters on the English Nation) that Her Grace used to go to Wycherley's chambers in the Temple disguised as a country wench, in a straw hat, with pattens on and a basket in her hand, may be apocryphal, for disguise was superfluous in her case, but it shows how general was the opinion that, under such patronage as this, Wycherley's fortune as poet and dramatist was now made. King Charles, who had determined to bring up his son, the Duke of Richmond, like a prince, sought as his tutor a man as qualified as Wycherley to impart a "princely education", and it seems clear that, if not for Wycherley's marriage, the education of the young man would actually have been entrusted to him as a reward for having written Love in a Wood.

Whether Wycherley's experiences as a naval officer, which he alludes to in his lines "On a Sea Fight which the Author was in betwixt the English and the Dutch", occurred before or after the production of Love in a Wood is a point upon which opinions differ, but probably took place not only after the production of Love in a Wood but after the production of The Gentleman Dancing Master, in 1673. Macaulay claims that he went to sea simply because it was the "polite" thing to do so — because, as he says in the epilogue to The Gentleman Dancing Master, "all gentlemen must pack to sea". This second comedy was published in 1673, but was probably acted late in 1671. In The Gentleman Dancing Master the mingling of discordant elements destroys a play that would never in any circumstances have been strong.

It is, however, on his two last comedies — The Country Wife and The Plain Dealer — that sustain Wycherley's reputation. The Country Wife, produced in 1672 or 1673 and published in 1675, is full of wit, ingenuity, high spirits and conventional humour.

Wycherley's efforts to bring to the Duke of Buckingham's notice the case of Samuel Butler shows that the writer of even such heartless plays as The Country Wife may have generous impulses, while his defence of Buckingham, when the duke in his turn fell into trouble, show that the inventor of so shameless a fraud as that which forms the pivot of The Plain Dealer may in actual life possess that passion for fair play which is seldom believed to be an English quality. But among the "ninety-nine" religions with which Voltaire accredited England there is one whose permanency has never been shaken — the worship of gentility. To this Wycherley remained as faithful to the day of his death as Congreve himself. And, if his relations to that "other world beyond this", which the Puritans had adopted, were liable to change with his environments, it was because that "other world" was really out of fashion altogether.

It was after the success of The Plain Dealer that the turning point came in Wycherley's career. The great dream of all the men about town in Charles's time, as Wycherley's plays all show, was to marry a widow, young and handsome, a peer's daughter if possible — but in any event rich, and spend her money upon wine and women. While talking to a friend in a bookseller's shop at Tunbridge, Wycherley heard The Plain Dealer asked for by a lady who, in the person of the countess of Drogheda (Letitia Isabella Robartes, eldest daughter of the 1st Earl of Radnor and widow of the 2nd Earl of Drogheda), answered all the requirements. An introduction ensued, then love-making, then marriage — a secret marriage, probably in 1680, for, fearing to lose the king's patronage and the income therefrom, Wycherley still thought it politic to pass as a bachelor.

He had not seen enough of life to learn that in the long run nothing is politic but "straightforwardness". Whether because his countenance wore a pensive and subdued expression, suggestive of a poet who had married a dowager countess and awakened to the situation, or whether because treacherous confidants divulged his secret, does not appear, but the news of his marriage oozed out — it reached the royal ears, and deeply wounded the father anxious about the education of his son. Wycherley lost the appointment that was so nearly within his grasp — lost indeed the royal favour for ever. He never had an opportunity of regaining it, for the countess seems to have really loved him, and Love in a Wood had proclaimed the writer to be the kind of husband whose virtue prospers best when closely guarded at the domestic hearth. Wherever he went the countess followed trim, and when she did allow him to meet his boon companions it was in a tavern in Bow Street opposite to his own house, and even there under certain protective conditions. In summer or in winter he was obliged to sit with the window open and the blinds up, so that his wife might see that the party included no member of a sex for which her husband's plays had advertised his partiality.