A number of members of the Belfast Charitable Society were involved in the 1798 rebellion. Dr William Drennan, visiting physician to the Poor House, came up with the concept of an organisation to unite Catholic, Protestant and Dissenter, but stepped back from the organisation as it became more militant. Thomas McCabe, a prominent member of the Belfast Charitable Society, was active in the United Irishmen. Thomas lived at the Vicinage on Buttle’s Loney, behind the Poor House, on which St Malachy’s College now stands. It is said that much of the 1798 rebellion was planned in McCabe’s house.
Mary Ann McCracken’s brother, Henry Joy McCracken went into hiding after the Battle of Antrim. He was allegedly on his way to a ship to America to escape the Crown forces when he was captured. McCracken was put on trial and condemned to death for his part in the 1798 rebellion. He was hanged at the Market House. Following his death Mary Ann McCracken devoted herself to her work with the Belfast Charitable Society and others, especially around issues relating to women and children within the Poor House.
The Poor House was requisitioned by the military throughout the Rebellion and for some years afterwards. The Belfast Charitable Society were considered a hotbed of radical activity and therefore it was necessary to keep them to the side-lines of Belfast life for some time. The Committee were forced to meet in the Exchange until 1800 when they received permission to re-entered the Poor House. The work of the Belfast Charitable Society resumed as if the Rebellion never occurred and they continued their work to promote the care of those with ill-health and impoverished in Belfast.