O'Reilly accompanied her mother to meetings at Cooper Union and her father's friend, Victor Drury, helped instill in her an appreciation for the Italian nationalist Giuseppe Mazzini.

[3] At age 16, O'Reilly joined the Comte Synthetic Circle, a self-education group in the Lower East Side of New York.

Drury was a French-born intellectual, Knights of Labor activist, and anarchist; he had introduced O'Reilly to many books which helped compensate for her lack of formal education.

[1] She was supported in this and other activities by a wealthy Boston philanthropist named who, in 1897, provided O'Reilly with an annual salary, allowing her to leave wage work for full-time labor organizing.

In part in reaction to what she thought was the betrayal of wealthy women supporters of the shirtwaist workers, in 1910, O'Reilly became a member of the Socialist Party of New York.

[3] Nicknamed as 'the agitator,' O'Reilly worked to empower the voice of women workers, rather than supporting their interests on the public platform alone.

[3] At this time O'Reilly was 45 years old and she began to suffer from the early stages of heart disease which would slowly trump her ability to be an energetic activist.

Within the nationalism movement in Ireland, radical aspects including a worker-centered agenda was called for in America –one that would "restore to producers the fruits of their labor".

Due to the lack of support from men in the labor movement, women turned to each other and formed alliances with those of middle-class status to seek remedies to aid "the working girl".

The occurrence of late marriage, coupled with a less family-centered ethnic tradition enabled Irish American women to gain employment.

Without the need to tend to marriage and household duties, women were allowed to work and thus contributed to the rise of Irish American female activists.

Leonora O'Reilly's experience growing up working-class allowed her to identify with the labor movement, which she saw as crucial for defending people, particularly women of her class.

[5] She argued industrial education was crucial for the liberation of working women, and trade schools for girls in the absence of apprenticeships available to boys.

After being formally introduced to labor rights efforts, in 1886 O'Reilly formed the cross-class Working Women's Society.

Together with other women activists, Leonora solidified the group and held discussions on how to build unionism among the exploited workingwomen in New York City.

The group was soon composed of shop women and factory operatives, including Alice L. Woodbridge and Ida Van Etten.

[6] At this time, Louise Perkins, a women's activist and philanthropist, had taken interest in O'Reilly's work, inviting her to membership in New York's Social Reform Club as this group would often speak on the contemporary issues surrounding the political economy.

[6] Because the WTUL consisted of working-class individuals who lacked education and money, they were unable to organize effectively without the aid of powerful allies.

[7] These progressive reformers attempted to steer workers away from radical influences, particularly the Socialist Party which O'Reilly and Rose Schneiderman, a fellow WTUL leader and organizer, were members of.

[7] The league seemed to them "to act out patronizing benevolence that had little to do with real coalition building", and the two leading organizes were angered by what they saw as attempts of allies to manipulate them.

This same year, O'Reilly joined the recently founded National Association for the Advancement of Colored People (NAACP), supporting African American rights.

[6] An ardent socialist, Leonora O'Reilly was a delegate to the 1915 Hague Women's Peace Convention, sailing through mine-laden waters aboard the MS Noordam.

Despite O'Reilly's lack of formal education, she was given the opportunity to teach a course at New York's New School for Social Research on 'the theory of the labor movement' in 1925 and 1926.

The holiday was not widely celebrated as many American and European socialists were less interested in the suffragist movement as the idea of promoting full women's rights was seen as subordinate to the economic advancement of male working class citizens.

Some believe that the first American IWD was on March 8, 1907, a day marking the 50th anniversary of the New York Strike of Female Textile Workers.

[8] Leonora O'Reilly became involved in support of the Irish Revolution, an uprising against British rule of Ireland founded in opposition to imperialistic policies.

The first was a boycott by dockworkers who refused to unload British cargoes across major American cities including New York, Boston, Philadelphia, New Orleans and Galveston.

[9] Regardless of its financial impact, the boycotting campaign highlighted a division within the American Federation of Labor (AFL) over the question of imperialism.