He completed an apprenticeship as a tailor, then moved to Scotland to find work, and later on to London.
While in London, he joined the Amalgamated Society of Journeymen Tailors, and gradually rose to prominence, taking a leading role in the strike of 1891.
[2] In 1893, Flynn was appointed as the union's London District Secretary, succeeding James MacDonald, and also took a place on the Executive Council.
George Keir, the General Secretary of the union, died later in the year, and Flynn was elected to the vacant office.
[1] Under his leadership, the union began accepting women as members and changed its name to the "Amalgamated Society of Tailors and Tailoresses".