Many Irish revolutionaries, including the leaders of the 1916 Easter Rising (Patrick Pearse, James Connolly, Tom Clarke, Seán Mac Diarmada, Joseph Plunkett, Éamonn Ceannt, Thomas MacDonagh), were imprisoned and executed in the prison by the orders of the UK Government.

As early as 1809, in his report, the Inspector had observed that male prisoners were supplied with iron bedsteads while females "lay on straw on the flags in the cells and common halls".

[4] Annie (Nan) Hogan of Cumann na mBan died at the age of 24 after being released from prison (September 1923) "in a very emaciated state" due to her participation in hunger strikes in Kilmainham and the North Dublin Union jails.

The Department of Education rejected this proposal seeing the site as unsuitable for this purpose and suggested instead that paintings of nationalist leaders could be installed in appropriate prison cells.

[9] An architectural survey commissioned by the Office of Public Works after World War II revealed that the prison was in a ruinous condition.

[10] In 1953 the Department of the Taoiseach, as part of a scheme to generate employment, re-considered the proposal of the National Graves Association to restore the prison and establish a museum at the site.

Leonard, a young engineer from the north side of Dublin, along with a small number of like-minded nationalists, formed the Kilmainham Gaol Restoration Society in 1958.

In order to offset any potential division among its members, the society agreed that they should not address any of the events connected with the Civil War period in relation to the restoration project.

At this time the Irish government was coming under increasing pressure from the National Graves Association and the Old IRA Literary and Debating Society to take action to preserve the site.

Thus, when the society submitted their plan in late 1958 the government looked favourably on a proposal that would achieve this goal without occasioning any significant financial commitment from the state.

[14] In February 1960 the society's detailed plan for the restoration project, which notably also envisioned the site's development as a tourist attraction, received the approval of the notoriously parsimonious Department of Finance.

[15][16] Commencing with a workforce of sixty volunteers in May 1960,[17] the society set about clearing the overgrown vegetation, trees, fallen masonry and bird droppings from the site.

The final restoration of the site was completed in 1971 when Kilmainham Gaol chapel was re-opened to the public having been reroofed and re-floored and with its altar reconstructed.