Anna Brennan was the thirteenth child of Michael Brennan, farmer and his wife Mary nee Maher. She commenced medical studies at the University of Melbourne in 1904, but was not permitted to continue as she was 'too nervous to do the dissections'. She commenced the law course in 1906, graduating in 1909. At the university she became a member of the Princess Ida Club for women students, was an office bearer from 1907-1909 and remained a committee member until 1913. She represented the Princess Ida Club on the national Council of Women in 1912

She became a partner in her brother Frank's firm, specialising in the matrimonial field and campaigned for more equitable laws in relation to divorce. She was the second woman in Victoria to be admitted to practice.

Her commitment to her Catholic faith was evident in her involvement with the Catholic Women's Social Guild, lecturing and writing for its publications Women's Social Work and its successor Horizon.

Joan of Arc was an inspiration to her and she joined the forerunner of the St Joan's International Alliance, the Catholic Women's Suffrage Society in London. She was an inaugural member of the Victorian chapter of the St Joans' International Alliance when it was established in 1936 and was president from 1938-45 and 1948-62.

Sources used to compile this entry: Campbell, Ruth and Morgan, Margaret, 'Brennan, Anna Teresa (1879-1962)', in Australian Dictionary of Biography Online, Australian National University, 2006, http://www.adb.online.anu.edu.au/biogs/A070404b.htm.