Isabella Mayson was born on 14 March 1836 in Marylebone, London. She was the eldest of three daughters to Benjamin Mayson, a linen factor (merchant) and his wife Elizabeth (née Jerrom). Shortly after Isabella's birth the family moved to Milk Street, Cheapside, from where Benjamin traded. He died when Isabella was four years old, and Elizabeth, pregnant and unable to cope with raising the children on her own while maintaining Benjamin's Business, sent her two elder daughters to live with relatives. Isabella went to live with her recently widowed paternal grandfather in Great Orton, Cumberland, though she was back with her mother within the next two years.

After a brief education at a boarding school in Islington, in 1851 Isabella was sent to school in Heidelberg, Germany, accompanied by her stepsister Jane Dorling. Isabella became proficient in the piano and excelled in French and German; she also gained knowledge and experience in making pastry. She had returned to Epsom by the summer of 1854 and took further lessons in pastry-making from a local baker.

Around 1854 Isabella began a relationship with Samuel Orchart Beeton. His family had lived in Milk Street at the same time as the Maysons—Samuel's father still ran the Dolphin Tavern there—and Samuel's sisters had also attended the same Heidelberg school as Isabella. Samuel was the first British publisher of Harriet Beecher Stowe's Uncle Tom's Cabin in 1852 and had also released two innovative and pioneering journals: The Englishwoman's Domestic Magazine in 1852 and the Boys' Own magazine in 1855. The couple entered into extensive correspondence in 1855—in which Isabella signed her letters as "Fatty"—and they announced their engagement in June 1855. The marriage took place at St Martin's Church, Epsom, in July the following year, and was announced in The Times. Samuel was "a discreet but firm believer in the equality of women" and their relationship, both personal and professional, was an equal partnership. The couple went to Paris for a three-week honeymoon, after which Samuel's mother joined them in a visit to Heidelberg. They returned to Britain in August, when the newlyweds moved into 2 Chandos Villas, a large Italianate house in Pinner.

Within a month of returning from their honeymoon Isabella was pregnant. A few weeks before the birth, Samuel persuaded his wife to contribute to The Englishwoman's Domestic Magazine, a publication that the food Writers Mary Aylett and Olive Ordish consider was "designed to make women content with their lot inside the home, not to interest them in the world outside". The magazine was affordable, aimed at young middle class women and was commercially successful, selling 50,000 issues a month by 1856. Isabella began by translating French fiction for publication as stories or serials. Shortly afterwards she started to work on the cookery column—which had been moribund for the previous six months following the departure of the previous correspondent—and the household article. The Beetons' son, Samuel Orchart, was born towards the end of May 1857, but died at the end of August that year. On the death certificate, the cause of death was given as diarrhoea and cholera, although Hughes hypothesises that Samuel senior had unknowingly contracted syphilis in a premarital liaison with a prostitute, and had unwittingly passed the condition on to his wife, which would have infected his son.

As early as 1857 the Beetons had considered using the magazine columns as the basis of a book of collected recipes and homecare advice, Hughes believes, and in November 1859 they launched a series of 48-page monthly supplements with The Englishwoman's Domestic Magazine. The print block for the whole series of the supplements was set from the beginning so the break between each edition was fixed at 48 pages, regardless of the text, and in several issues the text of a sentence or recipe is split between the end of one instalment and the beginning of the next.

During the particularly bitter winter of 1858–59 Isabella prepared her own soup that she served to the poor of Pinner, "Soup for benevolent purposes"; her sister later recalled that Isabella "was busy making [the] soup for the poor, and the children used to call with their cans regularly to be refilled". The recipe would become the only entry in her Book of Household Management that was her own. After two years of miscarriages, the couple's second son was born in June 1859; he was also named Samuel Orchart Beeton. Hughes sees the miscarriages as further evidence of Samuel's syphilis.

The Beetons decided to revamp The Englishwoman's Domestic Magazine, particularly the fashion column, which the Historian Graham Nown describes as "a rather drab piece". They travelled to Paris in March 1860 to meet Adolphe Goubaud, the publisher of the French magazine Le Moniteur de la Mode. The magazine carried a full-sized dress pattern outlined on a fold-out piece of paper for users to cut out and make their own dresses. The Beetons came to an agreement with Goubaud for the Frenchman to provide patterns and illustrations for their magazine. The first edition to carry the new feature appeared on 1 May, six weeks after the couple returned from Paris. For the redesigned magazine, Samuel was joined as Editor by Isabella, who was described as "Editress". As well as being co-editors, the couple were also equal partners. Isabella brought an efficiency and strong Business acumen to Samuel's normally disorganised and financially wasteful approach. She joined her husband at work, travelling daily by train to the office, where her presence caused a stir among commuters, most of whom were male. In June 1860 Isabella and Samuel travelled to Killarney, Ireland, for a fortnight's holiday, leaving their son at home with his nurse. The Beetons enjoyed the sightseeing, although on the days it rained, they stayed inside their hotel and worked on the next edition of The Englishwoman's Domestic Magazine. Isabella was impressed with the food they were served, and wrote in her diary that the dinners were "conducted in quite the French style".

Samuel's Business decisions from 1861 were unproductive and included an ill-advised investment in purchasing paper—in which he lost £1,000—and a court case over unpaid bills. His hubris in Business affairs brought on financial difficulties and in early 1862 the couple had moved from their comfortable Pinner house to premises over their office. The air of central London was not conducive to the health of the Beetons' son, and he began to ail. Three days after Christmas his health worsened and he died on New Year's Eve 1862 at the age of three; his death certificate gave the cause as "suppressed scarlatina" and "laryngitis". In March 1863 Isabella found that she was pregnant again, and in April the couple moved to a house in Greenhithe, Kent; their son, who they named Orchart, was born on New Year's Eve 1863. Although the couple had been through financial problems, they enjoyed relative prosperity during 1863, boosted by the sale of The Queen to Edward Cox in the middle of the year.

In the middle of 1864 the Beetons again visited the Goubauds in Paris—the couple's third visit to the city—and Isabella was pregnant during the visit, just as she had been the previous year. On her return to Britain she began working on an abridged version of the Book of Household Management , which was to be titled The Dictionary of Every-Day Cookery. On 29 January 1865, while working on the proofs of the dictionary, she went into labour; the baby—Mayson Moss—was born that day. Isabella began to feel feverish the following day and died of puerperal fever on 6 February at the age of 28.

In May 1866, following a severe downturn in his financial fortunes, Samuel sold the rights to the Book of Household Management  to Ward, Lock and Tyler (later Ward Lock & Co). The Writer Nancy Spain, in her biography of Isabella, reports that, given the money the company made from the Beetons' work, "surely no man ever made a worse or more impractical bargain" than Samuel did. In subsequent publications Ward Lock suppressed the details of the lives of the Beetons—especially the death of Isabella—in order to protect their investment by letting readers think she was still alive and creating recipes—what Hughes considers to be "intentional censorship". Those later editions continued to make the connection to Isabella in what Beetham considers to be a "fairly ruthless marketing policy which was begun by Beeton but carried on vigorously by Ward, Lock, and Tyler". Those subsequent volumes bearing Isabella's name became less reflective of the original. Since its initial publication the Book of Household Management  has been issued in numerous hardback and paperback editions, translated into several languages and has never been out of print.

Isabella and her main work have been subjected to criticism over the course of the twentieth century. Elizabeth David complains of recipes that are "sometimes slapdash and misleading", although she acknowledges that Prosper Montagné's Larousse Gastronomique also contains errors. The television cook Delia Smith admits she was puzzled "how on earth Mrs Beeton's book managed to utterly eclipse ... [Acton's] superior work", while her fellow chef, Clarissa Dickson Wright, opines that "It would be unfair to blame any one person or one book for the decline of English cookery, but Isabella Beeton and her ubiquitous book do have a lot to answer for." In comparison, the food Writer Bee Wilson opines that disparaging Isabella's work was only a "fashionable" stance to take and that the cook's writing "simply makes you want to cook". Christopher Driver, the Journalist and food critic, suggests that the "relative stagnation and want of refinement in the indigenous cooking of Britain between 1880 and 1930" may instead be explained by the "progressive debasement under successive editors, revises and enlargers". David comments that "when plain English cooks" were active in their kitchens, "they followed plain English recipes and chiefly those from the Mrs Beeton books or their derivatives". Dickson Wright considers Beeton to be a "fascinating source of information" from a social history viewpoint, and Aylett and Ordish consider the work to be "the best and most reliable guide for the scholar to the domestic history of the mid-Victorian era".

Despite the criticism, Clausen observes that "'Mrs. Beeton' has ... been for over a century the standard English cookbook, frequently outselling every other book but the Bible". According to the Oxford English Dictionary, the term Mrs Beeton became used as a generic name for "an authority on cooking and domestic subjects" as early as 1891, and Beetham opines that "'Mrs. Beeton' became a trade mark, a brand name". In a review by Gavin Koh published in a 2009 issue of The BMJ, Mrs Beeton's Book of Household Management was labelled a medical classic. In Isabella's "attempt to educate the average reader about Common medical complaints and their management", Koh argues, "she preceded the family health guides of today". Robin Wensley, a professor of strategic management, believes that Isabella's advice and guidance on household management can also be applied to Business management, and her lessons on the subject have stood the test of time better than some of her advice on cooking or etiquette.

The reviews for Book of Household Management were positive. The critic for the London Evening Standard considered that Isabella had earned herself a household reputation, remarking that she had "succeeded in producing a volume which will be, for years to come, a treasure to be made much of in every English household". The critic for the Saturday Review wrote that "for a really valuable repertory of hints on all sorts of household matters, we recommend Mrs Beeton with few misgivings". The anonymous reviewer for The Bradford Observer considered that "the information afforded ... appears intelligible and explicit"; the reviewer also praised the layout of the recipes, highlighting details relating to ingredients, seasonality and the times needed. Writing in The Morning Chronicle, an anonymous commentator opined that "Mrs Beeton has omitted nothing which tends to the comfort of housekeepers, or facilitates the many little troubles and cares that fall to the lot of every wife and mother. She may safely predict that this book will in Future take precedence of every other on the same subject." For the 1906 edition of the book, The Illustrated London News's reviewer considered the work "a formidable body of domestic doctrine", and thought that "the book is almost of the first magnitude".

Following the radio broadcast of Meet Mrs. Beeton, a 1934 comedy in which Samuel was portrayed in an unflattering light, and Mrs Beeton, a 1937 documentary, Mayston Beeton worked with H. Montgomery Hyde to produce the biography Mr and Mrs Beeton, although completion and publication were delayed until 1951. In the meantime Nancy Spain published Mrs Beeton and her Husband in 1948, updated and retitled in 1956 to The Beeton Story. In the new edition Spain hinted at, but did not elucidate upon, on the possibility that Samuel contracted syphilis. Several other biographies followed, including from the Historian Sarah Freeman, who wrote Isabella and Sam in 1977; Nown's Mrs Beeton: 150 Years of Cookery and Household Management, published on the 150th anniversary of Isabella's birthday, and Hughes's The Short Life and Long Times of Mrs Beeton, published in 2006. Isabella was ignored by the Dictionary of National Biography for many years: while Acton was included in the first published volume of 1885, Isabella did not have an entry until 1993.

There have been several television broadcasts about Isabella. In 1970 Margaret Tyzack portrayed her in a solo performance written by Rosemary Hill, in 2006 Anna Madeley played Isabella in a docudrama, and Sophie Dahl presented a documentary, The Marvellous Mrs Beeton, in the same year.

The literary Historian Kate Thomas sees Isabella as "a powerful force in the making of middle-class Victorian domesticity", while the Oxford University Press, advertising an abridged edition of the Book of Household Management, considers Isabella's work a "founding text" and "a force in shaping" the middle-class identity of the Victorian era. Within that identity, the Historian Sarah Richardson sees that one of Beeton's achievements was the integration of different threads of domestic science into one volume, which "elevat[ed] the middle-class female housekeeper's role ... placing it in a broader and more public context". Nown quotes an unnamed academic who thought that "Mrs Beetonism has preserved the family as a social unit, and made social reforms a possibility", while Nicola Humble, in her history of British food, sees The Book of Household Management  as "an engine for social change" which led to a "new cult of domesticity that was to play such a major role in mid-Victorian life". Nown considers Isabella

The Book of Household Management has been edited, revised and enlarged several times since Isabella's death and is still in print as at 2016. Food Writers have stated that the subsequent editions of the work were far removed from and inferior to the original version. Several cookery Writers, including Elizabeth David and Clarissa Dickson Wright, have criticised Isabella's work, particularly her use of other people's recipes. Others, such as the food Writer Bee Wilson, consider the censure overstated, and that Beeton and her work should be thought extraordinary and admirable. Her name has become associated with knowledge and authority on Victorian cooking and home management, and the Oxford English Dictionary states that by 1891 the term Mrs Beeton had become used as a generic name for a domestic authority. She is also considered a strong influence in the building or shaping of a middle-class identity of the Victorian era.