Acheson is born around 1744-45. He is the eldest son of Archibald Acheson, 1st Viscount Gosford, and his wife, the former Mary Richardson. His paternal grandfather is Sir Arthur Acheson, 5th Baronet, and his maternal grandfather is John Richardson of Rich Hill. His father succeeds to the baronetcy in 1748 upon the death of his father, and is subsequently created Baron Gosford in 1776 and Viscount Gosford in 1785.
In 1774, Acheson marries Millicent Pole, daughter of Lieutenant-General Edward Pole, who is descended from the Poles of Radbourne Hall in Derbyshire, and Olivia (née Walsh) Pole, a daughter and heiress of John Walsh of Ballykilcavan. The have seven children, two of whom die at a young age.
Acheson is a Member of Parliament (MP) for Old Leighlin from 1783 until 1791. He serves as governor of County Armagh at the time of the Armagh disturbances of 1795 and on December 28 denounces the Protestant extremists:
“It is no secret that a persecution is now raging in this country… the only crime is… profession of the Roman Catholic faith. Lawless banditti (Orange Order) have constituted themselves judges… and the sentence they have denounced… is nothing less than a confiscation of all property, and an immediate banishment.”
Upon the death of his father in 1790, Acheson succeeds to the viscountcy. He is subsequently created Earl of Gosford in February 1806.
(Pictured: “Arthur Acheson (c.1742–1807), 2nd Viscount, 1st Earl of Gosford,” oil on canvas by Gilbert Stuart)