William Knox began life in Ulster as the precocious child of a strongly evangelical Anglican family, and throughout a long career spent in service to the crown, he girded himself with his faith and a dogged allegiance to imperial authority. As the quintessential Anglo-Irish power seeker, Knox always remained something of a political outsider, even while enjoying a positions of great prestige and influence in colonial circles. Never afraid of controversy, quick to publish, and not infrequently differing with administrative positions, he never shrank from a defense of imperial privilege and power. Instead, Knox came to articulate an intricate imperial theory, vested in a spiritually charged paternalism and a philosophy of paternal power and filial obligation.
Although little is known about his formal education, Knox is known to have attended Trinity College (Dublin) for a time, where he fell under the sway of the noted Anglican scholar Philip Skelton. But it was America, rather than Ireland, that became Knox's pole star. Under the political aegis of Richard Cox, the young man attracted the attention of Lord Halifax, and when Henry Ellis was appointed governor of Georgia in 1757, Knox followed with a seat on the colonial council and with the position of provost marshal. Ever attentive to his political interests, Knox inculcated himself into a network of powerful southern colonial officials, including Ellis, William Henry Lyttelton (Governor of South Carolina and later Jamaica, not to mention godfather to Knox's son), and Charles Garth, colonial agent for South Carolina. During Knox's four years residence in Savannah, the colony prospered, and Knox ensured his personal prosperity through the acquisition of extensive land holdings in Georgia and the Carolinas and by carefully nurturing the fragile commercial interests of the colony. On the eve of the Revolution, his American estates had swelled to almost 8,400 acres under rice cultivation, worked by 122 slaves.
A committed evangelical, Knox saw little conflict between his religion and his status as a slave-holder. Over the course of his career, he developed an early version of the "positive good" argument for slavery, best displayed in an open letter to its principal evangelical opponent, William Wilberforce. As far as the physical condition of slaves was concerned, Knox remarked, they were no worse off in colonial slavery than in the Africa, but because Christianity was offered them in the colonies, their moral condition was far superior. While he asserted that Africans were innately dull witted, he insisted that they were nonetheless spiritually capable, and concluded that the paternal authority that structured slavery offered the most effective means of spreading Christianity among Africans. Consistent in his beliefs, he argued that Indians, more quick witted, could also be brought to Christianity if it were presented in a way that would not seem to threaten their cultural integrity.
Knox's departure from Georgia in 1761 initiated an incremental rise in his status within the circles of imperial power. In London, he cultivated Lord Grosvenor as friend and patron, and through him, obtained an entree to George Grenville, who was to become his political idol and ultimately, close friend. Winning appointment as Colonial Agent for Georgia and East Florida during the colonial crises of the early1760s, Knox emerged as an uncompromising supporter of the administration, though he appears to have harbored a limited sympathy for the colonists among whom he had lived and amassed his estate. Although Knox initially opposed Grenville's proposal to enforce the Stamp Act, arguing for concessions to the colonists provided they acknowledge the authority of Parliament, his overriding concern was that Parliamentary authority remain unabridged and preferably uncontested. He went to considerable lengths to lobby among his fellow colonial agents to draft petitions against the Act that did not question parliamentary authority, and his efforts may actually have contributed to repeal of the Act in 1766. But at the height of the controversy in 1765, he published two pamphlets underscoring his refusal to side with those opponents of the Stamp Act who questioned parliamentary authority, and providing a step by step demolition of arguments for colonial immunity. His pamphlets so enraged the Georgia Assembly, that they dismissed him from office.
Soon after the creation of the secretaryship for America in 1770, Knox was appointed undersecretary, serving under Hillsborough, Dartmouth, Germain, and Welbore Ellis until the office was dissolved in 1782. As a supporter of the North ministry's American policies, Knox consistently mirrored and reinforced Germain's belief that the rebellion could easily be defeated provided no concessions were made, though in his own mind maintaining a perspective on American affairs that attempted to preserve the imperial relation through a careful balance of concession and coercion. To encourage American commitment to British rule and discourage democratic impulses, he proposed the creation of a colonial aristocracy and the inclusion in parliament of representatives from the American colonies. The timing of his proposal, however, could not have been worse. Shortly after its appearance in 1777, news of Burgoyne's surrender at Saratoga reached London, effectively squelching any calls for such "concessions." A second consequence of the defeat at Saratoga was a shake-up of the Colonial Office, resulting in the dismissal of undersecretary Christian D'Oyley, who had been charged with overseeing the military aspects of colonial affairs. Knox survived the purge, and in the wake of the turmoil, grew increasingly in Germain's trust, rewarded with an ever increasing burden of responsibilities.
Knox's optimism about the course of the war grew disconcertingly stronger after 1780, and as late as the middle of 1781, he remained confident that Cornwallis' campaign in Virginia would result in an overwhelming victory for British arms. For this reason, the defeat at Yorktown was all the more devastating, and when Germain resigned from office early in 1782, Knox knew that his head would soon follow: as a particularly vocal advocate for prosecuting the war, he stood out as a particularly visible target. The new ministry, headed by Lord Shelburne, offered him a brief reprieve, but by April, 1782, he was out of office, the office itself abolished.
With his estates in Georgia confiscated, his finances impaired, and his hopes dashed, Knox became an intransigent opponent of reconciliation with America or recognition of its independence, hoping somehow to restore some vestige of the imperial relationship that he had struggled so hard to preserve. Partially out of self-interest, he turned his considerable energies to protecting the cause of the Loyalist refugees, and during the last twenty years of his life, he became deeply engaged in Loyalist interests in Canada, recognizing in them the realization of his own commitment to a paternalist system of authority and deference. The province of New Brunswick was established largely at his suggestion in 1784, and its lands were granted to Loyalist refugees from New York and New England. Furthermore, he served as attorney for the claims of the Georgia Loyalists following the death of James Wright in 1786. Not surprisingly, Knox also maintained a deep interest in Irish affairs from at least the mid-1770s, advocating a program that might be seen as paralleling his vision for America, featuring a restricted Catholic emancipation and liberalized trade in Ireland in the interest of strengthening imperial power there. He died in Ealing, near London, on August 25, 1810.