Lefevre, Madeleine Septimia Shaw- (1835–1914), college head, was born on 6 May 1835, the seventh child and fourth daughter of Sir John George Shaw-Lefevre (1797–1879), civil servant, and his wife, Rachel Emily Wright (1801–1885). George John Shaw-Lefevre, Baron Eversley, was an elder brother. She was educated at home in the succession of London residences taken by her father in his official career. During 1866–7 she visited her sister Rachel and brother-in-law, Arthur Charles Hamilton Gordon, in New Brunswick and Trinidad, where the latter was colonial governor.

Though she must have learned much from the conversation of her family, Madeleine Shaw-Lefevre, who, like three of her sisters, remained unmarried, was drawn late into public work. Her involvement in social work probably came about through her friendship with Lady Ducie (her brother's mother-in-law), a founder member of the Workhouse Visiting Society and connected with the National Association for the Promotion of Social Science. By 1877 Madeleine was on the committee of the Metropolitan Association for Befriending Young Servants, founded by Mrs Nassau Senior, and was an active ‘visitor’ on behalf of the association.

Madeleine Shaw-Lefevre's social work brought her to the attention of the committee of the council of Somerville Hall, Oxford, who, early in 1879, were seeking a warden for the newly founded undenominational hall for women students. Choice of a head for the institution was difficult because undefined: there was in 1879 no body of women distinguished by academic qualifications or by professional public service. Madeleine Shaw-Lefevre was not in the original shortlist, but was approached by John Percival, president of Trinity College and chairman of the council, and was elected on 3 May 1879. In her brief period of committee work she had acquired a reputation for hard work, wisdom, and tact, while her family's Liberal political connections further recommended her to the Somerville council. Her father, as vice-chancellor of London University, had privately favoured the earliest moves to open London degrees to women, and her brother, who promoted reform of the law relating to married women's property, was an energetic fund-raiser for Somerville. She had the additional qualification of having been, since 1885, a trustee at Bedford College for Women in London.

Miss Shaw-Lefevre was a reluctant candidate. She loved family life and dreaded the solitariness of her new position. She accepted it for one year only, and that on condition that she need not stay in Oxford during vacations. She was paid £100, with free board and lodging. Somerville Hall was housed in Walton Manor, a simple house, less grand than the homes of some of its students, set in three rough acres of paddock off the Woodstock Road. Living conditions must have seemed austere to the warden. Her duties were not onerous. There were twelve students in 1879, and the numbers did not rise above forty-three in her time. In 1885 the West Buildings (still little changed) were opened. West Buildings were run by a deputy warden, with their own drawing-room and dining-room. Students from House and West would pay calls on one another, leaving cards as their mothers had taught them.

Miss Shaw-Lefevre's function was to make a women's hall of residence acceptable in an ancient university city where women had been treated with little respect outside a family setting. She sought the advice of Anne Jemima Clough, and modelled arrangements at Somerville on those of Newnham Hall, Cambridge (rather than those of Girton, which sought to copy the men's colleges). In collaboration with her deputy at Somerville, Clara Pater, she was responsible for what Charlotte Green, a member of the council, described as 'the wise establishment of precedents in the conduct of life in a women's college' (Green, 165). She successfully ensured that opponents of women at Oxford were given no opportunity to attack the new institution. She believed that the Hall should resemble a house party. A few of the first students were well-to-do, in a period when wealth displayed itself in dress, especially in millinery. Others were young and socially inexperienced. She steered them between dowdiness and ostentation. Yet her rule was not felt to be oppressive. Her father had friends in Oxford and she was a valued guest at dinner parties. Distinguished men as well as women visited the warden, giving at least one student the impression that 'Oxford passed in freely' to them. Ruskin, at first hostile to the idea of women students, came to tea, saw the girls playing tennis on the rough lawn, and presented his complete works and a case of cut sapphires, later set in a jewelled necklace to be worn as the principal's chain of office.

During Miss Shaw-Lefevre's principalship women began (1884) to be admitted to university examinations. Teaching was arranged by the Association for the Education of Women, under Mrs Bertha Johnson; the first woman tutor was appointed at Somerville in 1882. Somerville had no chapel. From the beginning it had asserted its religious independence. Miss Shaw-Lefevre was a traditional but not an enthusiastic Anglican. She read prayers daily in the dining-hall but never talked about religion. She was for her time widely travelled, taking leave of absence during 1885–6 to visit the Hamilton-Gordons in Ceylon.

Madeleine Shaw-Lefevre's dignified grace survives in the portrait hanging over the principal's chair in Somerville College. She carried her head beautifully. Ordinarily she had an aristocratic casualness in dress, but could appear when the occasion called for it as a very great lady. Elizabeth Wordsworth described her as 'the very antipodes of the clumsy, masculine blue-stocking who was the favourite bugbear of the opponents of women's education' (Wordsworth, 5). At fifty-four, in the last year of her principalship, she seemed to one student, the Indian feminist Cornelia Sorabji, 'a very old lady' (Willson, 307). She presided over the first decade of Somerville. Traditions acceptable to Oxford were formed. In her time eighty-two Somervillians went out into the world, thirteen of them with firsts. In 1889 she went back to live quietly with her unmarried sisters, remaining on the council of the college until her death at her home, Greenhill Farm, Farnham, Surrey, on 19 September 1914. She was buried, with others of her family, at Ascot.