Limerick

As a young man, Lane-Joynt was a Young Irelander, but later joined the Liberal party and was their chief Irish election agent. He was elected to Limerick Corporation for the Abbey Ward prior to being elected mayor in 1862. During his term, he refused a knighthood from George Howard, 7th Earl of Carlisle, the lord lieutenant. He was a Protestant, but he supported the Catholic clergy and improved tenants' rights as well as the foundation of a Catholic university and the disestablishment of the Church of Ireland. He did oppose Home Rule, which led to him resigning from the Liberal party in 1886. He was clerk of the crown for Limerick from 1857 to 1869, served as the Limerick Corporation's land agent and solicitor, and as a member of the Limerick Harbour Commissioners. In 1848 he was chair of the Limerick Celtic Society and in 1853 served as President of the Limerick Literary and Scientific Society. He was a patron of the Limerick Mechanics' Institute, providing funding for an evening adult school teacher. He proposed that a Limerick Athenaeum should be established, and bought the lease in 1854 of the former headquarters of St Michael's parish commissioners on Cecil Street. There he oversaw the construction of a lecture theatre that could hold 600 people. Opened in 1856, Lane-Joynt was the inaugural president of the Limerick Athenaeum. He later served as vice-president of the Association of Librarians, and saw the publication of Denis Florence MacCarthy's complete works in 1881.^[1][2]

Dublin

Lane-Joynt resigned in late 1863 from the Limerick Corporation, moving to Grange Abbey, Raheny, Dublin. He was elected to Dublin Corporation in for the Rotunda ward in 1864, initially as a councillor and then as an alderman. He sat on the Port and Docks Board, and from 1865 was Justice of the Peace for County Dublin and deputy lieutenant of Dublin. In 1867, he was elected Lord Mayor of Dublin. That year he attended the Great Exhibition in Paris and received the Legion of Honour by Napoleon III. In 1869, he resigned from the Dublin Corporation having been appointed the Crown and Treasury Solicitor, a position he held until its abolition in 1887. He had a residence at Grange Abbey, as well as at Lower Gardiner Street and Merrion Square.^[1][2]

In the early 1880s, Lane-Joynt sat on the Mansion House Relief Committee which oversaw the distribution of aid in the west of Ireland. Any residual funds were directed towards the building of landing slips and piers in the most dangerous fishing regions, under the direction of Lane-Joynt. He was also a member of the board of Irish Lights, and saw the construction of a lighthouse at the entrance to Kilronan Harbour, Inishmore.^[1]

County Clare

From 1873, he was estate agent for Henry White, 1st Baron Annaly, spending his summers in Clareville House, County Clare. There he often served on the local grand jury, and Keeper of the Hanaper and District Lieutenant for the county. From 1894, he was the county's High Sheriff. He advocated to White that he should provide his tenants with a free supply of water, which resulted in a public water fountain in Ballyvaughan being erected in 1875. He did also represent the White family in court, during the course of which a precedent was set that farms that could not be tilled were not governed by the Land Acts, which deprived many of the Whites' tenants' fair rent protections.^[1][3]