Mary was the eldest of seven children born to a County Cork father and an English mother. When she was a child, the family moved from England to Cork, and her father attempted to set up a tobacco factory there. When this enterprise failed he emigrated to Australia, leaving his family to cope as best they could.
Mary was a bright but solemn little girl. At seven she developed an infection in her foot and had to have it amputated, which forced her to limp along in a surgical boot for the rest of her life. Since this incident precluded her from the usual rough and tumble of childhood, Mary became bookish and rather introverted. After her father’s departure, she felt a huge sense of responsibility for all her siblings, especially her brother, Terence, who was five years her junior.
At twenty years of age, Mary secured a teaching post at a strict Benedictine-run convent school in Kent, England. Mary was a deeply devout Catholic and, while she never actually joined a religious order, she joined a lay Catholic organisation whose members pledged themselves to lives of chastity and study.
In 1904 Mary’s mother died and she returned to Cork to help look after the family. The next ten years saw Terence become more and more committed to his political ideals, while Mary, a member of both the Gaelic League and Inghínidhe na hÉireann, became more politically aware through supporting him and discussing matters with him.
She joined the Munster Women’s Franchise League (MWFL), but she was lukewarm about feminism, describing herself as a ‘conservative suffragist’. Mary had little argument with women’s and men’s respective roles in society, but she wanted women to have more access to education and career opportunities. Eventually, Mary abandoned the cause of suffrage altogether to devote herself to the cause of Irish independence. Meanwhile, alongside her growing political career, she carried on teaching.
By 1914 Terence was deeply immersed in Sinn Féin and Mary was holding Cumann na mBan meetings in the MacSwiney living room. In those days she was not keen on the idea of armed conflict – though she later came to see republican fighting as ‘a just war’ against oppression – and she felt the Easter Rising of 1916 was premature.
Immediately after the Rising, Terence was arrested and sent to a prison in Frongoch, North Wales, while Mary’s role in ‘holding the fort’ in Cork during Easter Week led to her arrest in her classroom at school. She was subsequently sacked, whereupon she borrowed money and opened St Ita’s, a school for girls, at 4 Belgrave Place, Wellington Road, Cork.
As Terence continued to be arrested, released and rearrested for his political activities, Mary also became more active in the Cork branch of Cumann na mBan, campaigning vigorously against British attempts to impose conscription during World War I. In the general election of 1918, Terence was one of the thirty-six candidates elected to the first Dáil Éireann from their jail cells and Cork became a republican stronghold.
In March 1920 the lord mayor of Cork, Tomás MacCurtain, was murdered in his own home by members of the Royal Irish Constabulary (RIC). Terence MacSwiney took his place as mayor and shortly afterwards was arrested by the authorities on a trumped-up charge of possession of ‘sensitive’ documents. He immediately went on a hunger strike in protest at the illegality of his arrest. He fasted all the way through his trial, conviction and journey to imprisonment in England. On 25 October 1920, seventy-four days after beginning his strike, he died at Brixton Prison, London.
Mary managed the publicity surrounding her brother’s hunger strike and death. Always direct and confrontational, she made it plain that she believed the British government had let her brother die deliberately to provoke the sort of outrage that would require martial law to be deployed in Ireland. Her own response to his death was to become completely single-minded in her desire for an unequivocal Irish republic. After his funeral, she and Terence’s widow, Muriel, embarked on a well-attended American lecture tour, publicising Terence’s death and campaigning for his ideals. As she became more confident in the public eye, her style became more aggressive and she became known for her intractability.
Mary was still in the USA during Ireland’s general election of 1921, but her name was put forward and she was easily voted in as TD for Cork City. She was horrified when Michael Collins and Arthur Griffith signed the Anglo-Irish Treaty in 1921, and was convinced most of her colleagues in the Dáil would reject it. But despite her three-hour speech in defence of ‘the Irish Republic and the government of the Republic of Ireland, which is Dáil Éireann, against all enemies, foreign and domestic’ – the cause for which her brother had died – the Dáil voted narrowly in favour of the Treaty. Mary found herself going head-to-head with those who had a different approach to the issue of Irish independence.
Mary threw her support behind Eamon de Valera during the Civil War. She toured Ireland, arguing her brand of resolute republicanism and maintaining her opposition to the provisional government and her loyalty to the First Dáil of 1919. She was eventually arrested in Dublin and jailed in Mountjoy where she deployed her most effective weapon: hunger strike. It was obviously unthinkable that Terence MacSwiney’s sister should starve to death in the same way he had. This fact, plus Cumann na mBan’s huge publicity campaign, ensured Mary’s release in late 1922, four days after she had received the Last Rites from a Catholic priest.
In 1923 Mary toured again, was arrested again, went on hunger strike again (this time in the company of Maud Gonne) and was again released. She joined the Women’s Prisoners’ Defence League (WPDL), a band of mothers, wives and sisters of imprisoned and executed republicans.
When Eamon de Valera started to engage in constitutional politics with the hated Free State government, Mary was appalled and became estranged from her leader; she refused even to recognise the legitimacy of the Free State government. In 1926 she refused to join de Valera’s Fianna Fáil party and lost her Dáil seat the following year.
Thereafter, Mary became less and less relevant as her intransigence in the face of changing realities isolated her more and more from the main political action. Throughout the 1930s she continued to regard herself as the true voice of ‘old-guard’ republicanism, which still believed in the legitimacy of the First Dáil of 1919. She fell out with de Valera, Sinn Féin and even Cumann na mBan over the purity of their republican ideals. Believing that she, and she alone, occupied the moral high ground, Mary also fell out with the Roman Catholic Church. Eventually, the surviving members of the First Dáil signed over their authority to hard-core republicans: the newly resurgent Irish Republican Army (IRA).
Now in her sixties, Mary was beginning to suffer a variety of illnesses and was going blind due to cataracts. She had to reduce her political activity to writing furious letters to the newspapers. The mainstay in her frustrated life was Terence’s now-teenaged daughter, Máire Óg, whom she lovingly reared after his death. Although she remained an unrepentant republican to the very end, her political activities continued to decrease until her death at her Dublin home in the spring of 1942. She is buried in Cork City, near her brother.