Mary Josephine Crampton was born, probably in 1857 or 1858, in County Kilkenny, Ireland, the daughter of Mary O'Brien and her husband, Patrick Crampton, a shoesmith. Mary was brought up in the Catholic faith and, although literate, had little formal education. At the age of 16 she signed on in Waterford as a general servant for an assisted passage to New Zealand. She arrived in Wellington on the Woodlark on 14 March 1874.
Mary Crampton married Edward Player, a storeman, on 10 May 1877 at St Mary of the Angels Catholic Church, Wellington. An Englishman and Protestant, Edward was better educated than Mary but, like her, was poor. After a time he ran a small grocery store, and when that failed became a milkman, then a signwriter.
Between 1878 and 1890 Mary Player had six children, one of whom died in infancy. All were baptised in the Catholic faith. During these years Mary worked as a midwife and with her warm, generous personality gained a reputation for sympathy in assisting disadvantaged women. She was a member of the Wellington Ladies' Christian Association which administered a residence for unmarried mothers, the Alexandra Home for Friendless Women.
In 1894 Mary Player, an advocate of temperance, founded the Women's Social and Political League (WSPL). She chaired its inaugural meeting on 12 April and became the first president. With an entrance fee of 1s., the league's main objective was 'to spread knowledge amongst the women of Wellington on the political questions of the day'. Its platform included the enactment of equitable laws affecting marriage, divorce and the custody of children; the adjustment of women's wages and their hours of labour, and the appointment of inspectors to monitor these; and the appointment of women to hospital boards, charitable aid boards and other public bodies. During its first year the league held 51 meetings at which members delivered discussion papers.
Mary Player spoke on education, the single tax and the land question, and on 27 July 1894 proposed a state labour bureau for women. Possibly because of her own past experiences, her main concern was the welfare of domestic servants. She believed that a bureau, by vetting the character of both employee and employer, would help to foster good working relationships rather than generating class conflict, as a union might do. In 1895, shortly after Mary Player and two other league members had called on W. P. Reeves, minister of labour, to put forward their case, a Women's Branch was established in the Department of Labour.
On 9 February 1895 Daybreak, a new weekly periodical written by women for women, appeared in Wellington. Mary Player reported on her own activities and those of the WSPL. At the league's first annual general meeting on 10 April 1895 Marianne Tasker challenged Mary Player for the presidency. Player won only after exercising her casting vote in her own favour. Correspondents to the Evening Post variously condemned or supported Player, who was accused of a lack of openness and of being undemocratic.
Marianne Tasker led a breakaway movement from the WSPL and on 3 May 1895 set up the Women's Democratic Union – a more radical and union-oriented organisation. By becoming at that time a provisional director of Daybreak, Tasker also ensured substantial press coverage of the WDU at the expense of the WSPL.
Handicapped by lack of money, education, political experience and social standing, Mary Player was ill-equipped to handle the complexities of political infighting. On 2 September 1895 a major faction within the remaining membership led by Louisa Seddon reconfirmed a resolution endorsing the policies of the increasingly conservative Liberal government. As a result, at the 9 September meeting several members resigned. Mary Player resigned as president at the end of September and Louisa Seddon replaced her.
In 1897, when aged 40, Mary Player gave birth to her seventh child. Nevertheless, she continued her efforts to improve working conditions for women, and campaigned for the building of women's rest-rooms in Wellington city. However, the death of her husband on 22 November 1905 left Mary and her younger children homeless. From that time she took on any paid work, mostly 'incurable' nursing cases, which would provide the family with a home.
In later life Mary Player lived with her married daughters in various parts of New Zealand and assisted them in childbirth. She died on 5 January 1924 in Atawhai, Nelson, at the home of her youngest daughter. The coroner's verdict was 'Suicide by drowning while suffering from mental depression caused by serious internal ailment'. She was buried beside her husband in Karori cemetery.