Patrick Alphonsus Buckley was born probably in 1840 or 1841 near Castletownsend, County Cork, Ireland. The names of his parents are not known. He was educated at Queen's College in Cork, in Paris, and at the Université catholique de Louvain in Belgium. While there, in 1860, he was commissioned by the pope's private chaplain to take a band of volunteers from Ostend to Vienna to join the papal forces against the Piedmontese. Serving under General Lamoricière he was present at the battle of Castelfidardo, and was twice wounded before being taken prisoner.
After his release Patrick Buckley returned to Louvain, where he completed his licentiate. He went back to Cork, then in 1862 sailed for Queensland, Australia. In Brisbane he entered the law office of Charles Lilley, who later became premier and chief justice of Queensland. He was admitted to the Bar and began to practise in Brisbane, then moved to Melbourne where he was admitted to the Victorian Bar.
In 1865 Buckley moved to Wellington, New Zealand. At first he was in partnership with C. E. Button and W. S. Reid; then in 1867 he joined Robert Hart. Eventually he helped to found the law firm of Buckley, Stafford and Fitzherbert. He was a prominent member of the legal profession in Wellington, and in 1879 he attended the first meeting of the Wellington District Law Society.
Patrick Buckley was said to be strikingly handsome. He married Alice Jane Fitzherbert, the only daughter of William Fitzherbert, the colonial treasurer, at St James' Church, Hutt (Lower Hutt), on 3 April 1869. She was much younger than he was and very beautiful. An admirer of Alice Buckley was once found tarred and feathered and Patrick was believed to be responsible. The couple lived in Parliament Street, Lower Hutt, and were prominent members of the Wellington social élite. Alicetown in Lower Hutt was named after Alice, and Buckley Road, Island Bay, and Buckley Street, Lower Hutt, after Patrick.
In Wellington Patrick Buckley was actively involved in the affairs of the Catholic church and with Irish politics. He campaigned for Irish home rule; at a meeting he chaired on 15 March 1888 on home rule for Ireland he asked why it was that 'Englishmen who pose before the world as the personification of everything that is free, should withhold the hand of friendship, should not go hand in hand with Ireland.' Subsequently, Buckley was elected president of the Wellington branch of the Irish National Federation, a home rule organisation. However, he remained politically moderate. In 1868 he had refused to defend an Irish priest, W. J. Larkin, who had been arrested after disturbances on the West Coast and charged with seditious libel.
Buckley was the member for Karori and Makara in the Wellington Provincial Council in 1872 and a member of the Wellington City Council from 1871 to 1873. In 1878 he was appointed to the Legislative Council. He was a member of the Stout–Vogel ministry from 1884 to 1887, the Ballance ministry from 1891 to 1893, and the Seddon ministry from 1893 to 1895. Although he remained in high office throughout, he was an adminstrator of his portfolios rather than an innovator of legislation. At various times he was leader of the Legislative Council, colonial secretary, attorney general, postmaster general and minister of marine. While in the Stout–Vogel ministry he was involved in the proposed annexation of Samoa. In 1892 he was appointed a KCMG in recognition of his long and valuable services to the colony.
In December 1895 Patrick Buckley retired from the Legislative Council and was appointed a judge of the Supreme Court of New Zealand. However, he held office only for about five months before dying suddenly at Lower Hutt on 18 May 1896, aged 55 years. He was survived by his wife, Alice; they are not known to have had any children.