Charles Patrick John Coghlan was born on 24 June 1863 in King William's Town, British Kaffraria (part of the Cape Colony from 1866). He had three elder brothers. His father, James Coghlan, was from Ireland and was a Catholic; he had arrived in South Africa in 1851 as a private in the British Army, having enlisted to escape the Great Famine of Ireland. After fighting in the Eighth Xhosa War of 1850–53 with the 2nd (The Queen's Royal) Regiment of Foot, James was stationed in the Keiskamma mountains; he settled there with his wife Isabella Mary (née Maclaren), who was originally from Dumbartonshire, Scotland. They moved to King William's Town after Coghlan's discharge from the military and the birth of their first child, a boy also called James. The elder James Coghlan would become a town councillor in King William's Town.