Haywood gave conflicting accounts of her own life; her origins remain unclear and there are presently contending versions of her biography. For example, it was once mistakenly believed that she married the Rev. Valentine Haywood.

Some details have been widely accepted however: She was probably born in Shropshire, England. Her first entry into the public record is in Dublin, Ireland, in 1715 when she was listed as "Mrs. Haywood" in Thomas Shadwell's Shakespeare adaptation, Timon of Athens; or, The Man-Hater at Smock Alley Theatre. She had an open live-in relationship with William Hatchett, the father of her second child. She also had a child with Richard Savage.

Haywood’s writing career began in 1719 with the first two installments of Love in Excess, a novel, and ended in the year she died with conduct books The Wife and The Husband, and the biweekly periodical The Young Lady. She wrote in several genres and many of her works were published anonymously. There is much of Haywood’s writing career that still remains unknown.

She fell ill in October 1755 and died on 25 February 1756. She was buried in Westminster. For unknown reasons, her burial was delayed by about a week and her death duties remain unpaid.

Haywood, Delarivier Manley and Aphra Behn were known as the Fair Triumvirate of Wit and are considered the most prominent writers of amatory fiction. Eliza Haywood’s prolific fiction develops from titillating romance novels and amatory fiction during the early 1720s to works focused more on “women's rights and position” (Schofield, Haywood 63) in the later 1720s into the 1730s. In the middle novels of her career, women were locked up, tormented and beleaguered by domineering men. In the later novels of the 1740s and 1750s however, marriage was viewed as a positive situation between men and women.

Due to the economy of publishing in the 18th century, her novels often ran to multiple volumes. Authors were paid only once for a book and received no royalties; a second volume meant a second payment.

Haywood’s first novel, Love in Excess or The Fatal Enquiry (1719—1720) touches on themes of education and marriage. Termed an amatory bodice-ripper by some, this novel is also notable for its treatment of the fallen woman. D’Elmonte, the novel's male protagonist, reassures one woman that she should not condemn herself: “There are times, madam”, he says “in which the wisest have not power over their own actions.” The fallen woman is given an unusually positive portrait.

Idalia; or The Unfortunate Mistress (1723) is divided into three parts. In the first, Idalia is presented as a young motherless, spoiled, and wonderful Venetian aristocrat whose varied amorous adventures are to carry her over most of Italy. Already in Venice she is sought by countless suitors, among them the base Florez, whom her father forbids the house.

One suitor, who is Florez’s friend, Don Ferdinand, resigns his suit, but Idalia’s vanity is piqued at the loss of an even a single adorer, and more from perverseness than from love she continues to correspond with him. She meets him, and he eventually effects her ruin. His beloved friend, Henriquez conducts her to Padua, but becomes the victim of her charms; he quarrels with Ferdinand, and they eventually kill each other in a duel.In the second part, Henriquez’ brother, Myrtano, succeeds as Idalia’s principal adorer, and she reciprocates his love. She then receives a letter informing her about Myrtano’s engagement to another woman, so she leaves for Verona, hoping to enter a convent. On the road her guide takes her to a rural retreat with the intention of killing, but she escapes to Ancona from where she takes ship for Naples.

The sea captain pays her crude court, but just in time to save her from his embraces the ship is captured by corsairs commanded by a young married couple. Though the heroine is in peasant dress, she is treated with distinction by her captors. Her history moves them to tears and they in turn are in the midst of relating to Idalia the involved story of their courtship when the vessel is wrecked in a gale.

In the third part, we find Idalia borne ashore on a plank; succoured by cottagers she continues her journey towards Rome in a man’s clothes. On the way robbers beat her and leave her for dead but. She is found and taken home by a lady, Antonia, who falls in love with her. Idalia later discovers that Antonia’s husband is her dear Myrtano, but overcome by remorse, dies by the same knife. Their happiness is interrupted by the jealousy of his wife, who first tries to poison everyone and after appeals to the Pope to separate them. Idalia is taken to Rome first in a convent where she leads a miserable life, persecuted by all the young gallants of the city. Then one day she sees Florez, the first cause of her misfortunes. With thoughts of revenge, she sends him a billet, but Myrtano, keeps the appointment instead of Florez. Not recognising her lover, muffled in a cloak, Idalia stabs him, and then dies by the same knife.

Fantomina; or Love in a Maze (1724) is a short story about a woman who assumes the roles of a prostitute, a maid, a widow, and a Lady in order to repeatedly seduce a man named Beauplaisir. Schofield points out that, “Not only does she satisfy her own sexual inclinations, she smugly believes that ‘while he thinks to fool me, [he] is himself the only beguiled Person’” (50). This novel asserts that women have some access to power in the social sphere, one of the recurring themes in Haywood’s work.

The Adventures of Eovaii: A Pre-Adamitical History (1736) was also titled The Unfortunate Princess (1741). It is a satire of Prime Minister Robert Walpole, told through a sort of oriental fairy tale.

The Anti-Pamela; or Feign’d Innocence Detected (1741) is a satirical response to Samuel Richardson’s didactic novel Pamela, or, Virtue Rewarded (1740). It makes fun of the idea of bargaining one’s maidenhead for a place in society. Contemporary writer Henry Fielding also responded to Pamela with An Apology for the Life of Mrs. Shamela Andrews (1741).

The Fortunate Foundlings (1744) is a picaresque novel in which two children of opposite sex experience the world differently, according to their gender.

The History of Miss Betsy Thoughtless (1751) is a sophisticated, multi-plot novel that has been deemed the first novel of female development in English. Betsy leaves her emotionally and financially abusive husband Munden and experiences independence for a time before she decides to marry again. Written a few years before her marriage conduct books were published, the novel contains advice on marriage in the form of quips from Lady Trusty. Her “patriarchal conduct-book advice to Betsy is often read literally as Haywood's new advice for her female audience. However, Haywood's audience consisted of both men and women, and Lady Trusty's bridal admonitions, the most conservative and patriarchal words of advice in the novel, are contradictory and impossible for any woman to execute completely” (Stuart).

Betsy Thoughtless represents an important change in the 18th century novel. It portrays a mistaken but intelligent and strong-willed woman who gives way to society’s pressures toward marriage. According to Backsheider, Betsy Thoughtless is a novel of marriage, rather than the more popular novel of courtship and thus foreshadows the type of domestic novel that would culminate in the 19th century such as Charlotte Brontë’s Jane Eyre. Instead of concerning itself with attracting a partner well, Betsy Thoughtless is concerned with marrying well, and its heroine learns that giving way to the role of women in marriage can be fulfilling.

Haywood’s fiction also includes:

• The British Recluse (collected edition 1724)
• The Injur’d Husband
• Idalia; or The Unfortunate Mistress (1723)
• Lasselia; or The Self-Abandon’d
• The Rash Resove; or, The Untimely Discovery (1723)
• Secret Histories, Novels, and Poems (4 volumes, 1724)
• The Masqueraders; or Fatal Curiosity (1724-5)
• The Fatal Secret; or, Constancy in Distress (1724)
• The Surprise (1724)
• The Arragonian Queen: A Secret History (1724)
• The City Jilt; or, The Alderman Turn’d Beau (1726)
• The Force of Nature; or, The Lucky Disappointment (1724)
• Memoirs of a Certain Island Adjacent to the Kingdom of Utopia (1725)
• Bath Intrigues: in four Letters to a Friend in London (1725)
• Memoirs of the Baron de Brosse (1724)
• The Secret History of the Present Intrigues of the Court of Carimania (1726)
• Letters from the Palace of Fame (1727)
• The Unequal Conflict (1725)
• The Fatal Fondness (1725)
• The Mercenary Lover; or, the Unfortunate Heiresses (1726)
• The Double Marriage; or, The Fatal Release (1726)
• The Distressed Orphan; or, Love in a Madhouse (1726)
• Cleomelia; or The Generous Mistress (1727)
• The Fruitless Enquiry (1727)
• The Life of Madam de Villesache (1727)
• Philadore and Placentia (1727)
• The Perplex’d Dutchess; or Treachery Rewarded (1728)
• The Padlock; or No Guard Without Virtue (1728)
• Irish Artifice; or, The History of Clarina (1728)
• Persecuted Virtue; or, The Cruel Lover (1728)
• The Agreeable Caledonian; or, Memoirs of Signiora di Morella (1728)
• The Fair Hebrew; or, A True, but Secret History of Two Jewish Ladies (1729)
• Life’s Progress through the Passions; or, The Adventures of Natura (1748)
• Dalinda; or The Double Marriage (1749)
• A Letter from H------ G--------, Esq., One of the Gentlemen of the Bedchamber of the Young Chevalier (1750).
• The History of Jemmy and Jenny Jessamy (1753)
• The Invisible Spy (1754)

The Most detailed and up-to-date bibliography available is Patrick Spedding, A Bibliography of Eliza Haywood. London: Pickering and Chatto, 2004.

Haywood began her acting career in 1715 in Smock Alley Theatre in Dublin. By 1717, she had moved to Lincoln's Inn Fields, where she worked for John Rich. Rich had her rewrite a play called The Fair Captive. The play only ran for three nights (to the author's benefit), but Rich added a fourth night as a benefit for the second author, Haywood. In 1723, her first play, A Wife to be Lett, was staged.

During the second half of the 1720s, Haywood continued acting, and she moved over to the Haymarket Theatre to join with Henry Fielding in the opposition plays of the 1730s. In 1729, she wrote Frederick, Duke of Brunswick-Lunenburgh to honor the future George II of the United Kingdom. George II, as Prince of Wales, was a locus for Tory opposition to the ministry of Robert Walpole. As he had made it clear that he did not favor his father's policies or ministry, praise for him was demurral from the present king. Others, such as James Thomson and Henry Brooke, were also writing such "patriotic" (which is to say in support of the Patriot Whigs) plays at the time, and Henry Carey was soon to satirize the failed promise of George II.

Haywood's greatest success at Haymarket came with The Opera of Operas, an operatic adaptation of Fielding's Tragedy of Tragedies (with music by J. F. Lampe and Thomas Arne) in 1733. However, it was an adaptation with a distinct difference. Caroline of Ansbach had affected a reconciliation between George I and George II, and this meant an endorsement by George II of the Whig ministry. Haywood's adaptation contains a reconciliation scene, replete with symbols from Caroline's own grotto. This was an enunciation of a change by Haywood herself away from any Tory, or anti-Walpolean, causes that she had supported previously, and it did not go unnoticed by her contemporaries.

In 1735, she wrote a one-volume Companion to the Theatre. This book contains plot summaries of contemporary plays, literary criticism, and dramaturgical observations. In 1747 she added a second volume.

After the Licensing Act of 1737, the playhouse was shut against adventurous new plays.

While she was writing popular novels, Eliza Haywood was also working on periodicals, essays and manuals on social behaviour (conduct books). The Female Spectator (4 volumes, 1744—46), a monthly periodical, was written in answer to the contemporary journal The Spectator by Joseph Addison and Richard Steele. In The Female Spectator, Haywood wrote in four personas (Mira, Euphrosine, Widow of Quality and The Female Spectator) and took positions on public issues such as marriage, children, reading, education and conduct. It was the first periodical written for women by a woman and arguably one of Haywood’s most significant contributions to women's writing. Haywood followed a lead by contemporary John Dunton who issued the Ladies’ Mercury as a companion to his successful Athenian Mercury. Even though The Ladies' Mercury was a self-proclaimed women’s journal, it was produced by men (Spacks xii).

The Parrot (1746) apparently earned her questions from the government for political statements about Charles Edward Stuart.

Mary Stuart, Queen of Scots (1725) is termed a “hybrid" work by Schofield (103); being a work of non-fiction but making use of narrative techniques.Reflections on the Various Effects of Love (1726) is a didactic account of what can happen to a woman when she gives in to her passions. This piece demonstrates the sexual double standard that allow men to love freely without social consequence and women to be scandalized for doing the same.

The Wife and The Husband (1756) are conduct books for each partner in a marriage. The Wife was first published anonymously (by Mira, one of Haywood's personas from The Female Spectator); The Husband: in Answer to The Wife followed later the same year with Haywood’s name attached.

Like Daniel Defoe, Haywood worked on sensational pamphlets on the famous contemporary deaf-mute prophet, Duncan Campbell. These include A Spy Upon the Conjurer (1924) and The Dumb Projector: Being a Surprising Account of a Trip to Holland Made by Duncan Campbell (1925).

Eliza Haywood was active in politics during her entire career, although she had a party change around the time of the reconciliation of George II with Robert Walpole. She wrote a series of parallel histories, beginning with 1724's Memoirs of a Certain Island, Adjacent to Utopia, and then The Secret History of the Present Intrigues of the Court of Caramania in 1727. In 1746 her started another journal, The Parrot, which got her questioned by the government for political statements about Charles Edward Stuart, as she was writing just after the Jacobite Rising. This would happen again with the publication of A Letter from H-- G----g, Esq. in 1750. She grew more directly political with The Invisible Spy in 1755 and The Wife in 1756.

Haywood’s other works of non-fiction include:

Love-Letters on All Occasions Lately Passed between Persons of Distinction (1730).A Present for a Servant Maid ; or, the Sure Means of Gaining Love and Esteem (1743).[A revision.] A New Present for A Servant-Maid: containing Rules for her Moral Conduct, both with respect to Herself and her Superiors: The Whole Art of Cookery, Pickling, and Preserving, &c, &c. and every other Direction necessary to be known to render her a Complete, Useful and Valuable Servant. (in TEN BOOKS): G. Pearch, &c. 1771.Epistles for the Ladies (1749).

Haywood published eight translations of popular continental romances (Schofield). They include: Letters from a Lady of Quality (1721); La Belle Assemblée (1724) (translation of Madame de Comez’s novella); The Lady’s Philosopher's Stone (1723) (translation of Louis Adrien Duperron de Castera’s historical novel); Love in its Variety (translation of Matteo Bandello’s stories); The Disguis'd Prince (1728) (translation of Madame de Villedieu’s 1679 novel); The Busy-Body (1741, 42) (translation of de Mouhy's novel); and The Virtuous Villager (1742) (translation of Charles de Fieux's work).

Haywood is notable as a transgressive, outspoken writer of amatory fiction, plays, romance and novels. Paula R. Backscheider claims that “Haywood's place in literary history is equally remarkable and as neglected, misunderstood, and misrepresented as her oeuvre” (xiii intro drama). For quite some time Eliza Haywood was most frequently noted for her appearance in Alexander Pope's The Dunciad rather than for her own literary merits. Even though Alexander Pope made her a centerpoint in the heroic games of The Dunciad in Book II...she is, in Pope's view, "vacuous"--he does not dismiss her for being a woman, but for having nothing of her own to say. Pope attacks her for politics and for, implicitly, plagiarism. Unlike other "dunces", however, Pope's characterization does not seem to have been the cause of her obscurity. Rather, as literary historians came to praise and value the masculine novel and, most importantly, to dismiss the courtship novel and to exclude novels of eroticism, Haywood's works were rejected for more chaste or more overtly philosophical works.

In The Dunciad, the book sellers race each other to reach Eliza, and their reward will be all of her books and her company. She is for sale, in other words, in literature and society, in Pope's view. As with other "dunces", she was not without complicity in the attack. Haywood had begun to make it known that she was poor and in need of funds, and she seemed to be writing for pay and to please the undiscerning public.

Eliza Haywood is now regarded as "a case study in the politics of literary history" (Backscheider 100). She is also being reevaluated by feminist scholars and rated very highly. Interest in Haywood’s work has been growing since the 1980s. Her novels are regarded as stylistically innovative. Her plays and political writing attracted most of the attention in her own time, and she was a full player in the difficult public sphere.

Her novels, voluminous and frequent, are now regarded as stylistically innovative and important transitions from the erotic seduction novels and poetry of Aphra Behn (particularly Love-Letters Between a Nobleman and His Sister (1684)) and the straightforward, plainly spoken novel of Frances Burney. In her own day, her plays and political writing attracted the most comment and attention, and thus she was a full player in the difficult public sphere, but today her novels carry the most interest and demonstrate the most significant innovation.

Mary Anne Schofield's biography Eliza Haywood (1985) as well as Christine Blouch's article “The Romance of Obscurity” (1991) remain the most comprehensive resources on Haywood's background.