Mary Neal, the daughter of a successful businessman, was born in Edgbaston on 5th June 1860. She was educated at Birmingham Ladies' College but later became a student of economics.
In 1890 Mary Neal became a voluntary social worker at the West London Methodist Mission. The following year she met Emmeline Pethick. The two women became close friends. Emmeline later commented that Mary had a "strong sense of humour and a profound aversion from unreality". As Elizabeth Crawford, the author of The Suffragette Movement (1999), has pointed out: "Emmeline Pethick and Mary Neal left the Mission in order that they might carry on their social missionary work free from what they had come to perceive as the restrictions of its Methodist ethos and without the restrictions of institutional living."
In 1895 Mary Neal and Emmeline Pethick formed the Espérance Club that was influenced by the ideas of William Morris, Edward Carpenter, and Walt Whitman. This involved helping a group of young women establish a co-operative dressmaking business, Maison Espérance, in Wigmore Street. In 1900 the two women developed a hostel at Littlehampton for working girls' holidays. However, the partnership broke up when Emmeline married Frederick Lawrence.
In 1906 Mary Neal joined the Women Social & Political Union. She later became a member of the national committee of the WSPU. Unlike her close friend, Emmeline Pethick-Lawrence, she refused to take part in any militant action.
Mary Neal joined forces with Cecil Sharp, the brother of Evelyn Sharp, in order to revive English Folk Dance. In 1910 she published The Espérance Morris Book, which includes detailed description of 12 Morris dances and a selection of folk songs. Later that year she travelled to the United States where she lectured on folk dance.
In October 1912, Christabel Pankhurst told Emmeline Pethick-Lawrence and Frederick Pethick-Lawrence about the proposed arson campaign. When Emmeline and Frederick objected, Christabel arranged for them to be expelled from the the organisation. Emmeline later recalled in her autobiography, My Part in a Changing World (1938): "My husband and I were not prepared to accept this decision as final. We felt that Christabel, who had lived for so many years with us in closest intimacy, could not be party to it. But when we met again to go further into the question… Christabel made it quite clear that she had no further use for us."
Mary Neal also left the WSPU and became a "special commissioner" for Votes for Women, a newspaper owned by Emmeline Pethick-Lawrence and Frederick Pethick-Lawrence. On 6th February, 1914, she became one of the founding members of the United Suffragists. Other members included Evelyn Sharp, Lena Ashwell, John Scurr, George Lansbury, Gerald Gould, Hertha Ayrton, Louisa Garrett Anderson, Eveline Haverfield, Edith Zangwill, Israel Zangwill, Laurence Housman and Henry Nevinson. She was also a member of the Tax Resistance League.