The King's Royal Rifle Corps was an infantry rifle regiment of the British Army that was originally raised in British North America as the Royal American Regiment during the phase of the Seven Years' War in North America known in the United States as 'The French and Indian War.' Subsequently numbered the 60th Regiment of Foot, the regiment served for more than 200 years throughout the British Empire. In 1958, the regiment joined the Oxfordshire and Buckinghamshire Light Infantry and the Rifle Brigade in the Green Jackets Brigade and in 1966 the three regiments were formally amalgamated to become the Royal Green Jackets. The KRRC became the 2nd Battalion, Royal Green Jackets. On the disbandment of the 1st Battalion, Royal Green Jackets in 1992, the RGJ's KRRC battalion was redesignated as the 1st Battalion, Royal Green Jackets, eventually becoming 2nd Battalion, The Rifles in 2007.

The King's Royal Rifle Corps was raised in the American colonies in 1756 as the 62nd (Royal American) Regiment to defend the colonies against attack by the French and their indigenous allies. After Braddock's defeat in 1755, royal approval for a new regiment, as well as funds, were granted by parliament just before Christmas 1755 – hence the regiment's traditional birthday of Christmas Day. However, parliamentary delays meant that it was 4 March 1756 before a special act of parliament created four battalions of 1,000 men each to include foreigners for service in the Americas.

A regimental history compiled in 1879 states that, in November 1755, Parliament voted the sum of £81,000 for the purpose of raising a regiment of four battalions, each one thousand strong, for service in British North America. To provide experienced personnel, Parliament passed the Commissions to Foreign Protestants Act 1756 (29 Geo. 2. c. 5) The Earl of Loudoun, who as commander-in-chief of the Forces in North America, was appointed colonel-in-chief of the regiment. About fifty officers' commissions were given to Germans and Swiss, and none were allowed to rise above the rank of lieutenant-colonel.

According to a modern history of the regiment, the idea for creating this unique force was proposed by Jacques Prevost, a Swiss soldier and adventurer who was a friend of the Duke of Cumberland (the Duke was the King's third son and also Commander-in-Chief of the Forces). Prevost recognised the need for soldiers who understood forest warfare, unlike the regulars who were brought to America in 1755 by General Edward Braddock.

The regiment was intended to combine the characteristics of a colonial corps with those of a foreign legion. Swiss and German forest fighting experts, American colonists and volunteers from other British Army regiments were recruited. These men were Protestants, an important consideration for fighting against the predominantly Catholic French. The officers were also recruited from Europe – not from the American colonies – and consisted of English, Scots, Irish, Dutch, Swiss and Germans. It was the first time foreign officers were commissioned as British Army officers. In total, the regiment consisted of 101 officers, 240 non-commissioned officers and 4,160 enlisted men. The battalions were raised on Governors Island, New York. The regiment was renumbered the 60th (Royal American) Regiment in February 1757 when the 50th (Shirley's) and 51st (Pepperrell's) foot regiments were removed from the British Army roll after their surrender at Fort Oswego.

Among the distinguished foreign officers given commissions in the 60th (Royal Americans) was Henry Bouquet, a Swiss citizen, whose forward-looking ideas on tactics, training and man-management (including the unofficial introduction of the rifle and more practical clothing suited to bush-fighting) would come to be accepted as standard in the British Army many years in the future. Bouquet was commanding officer of the 1st battalion, and with his fellow battalion commanders, worked to form units that were better suited to warfare in the forests and lakes of northeast America.

Elements of the new regiment fought at Louisbourg in June 1758, the Cape Sable Campaign in September 1758 and Quebec in September 1759, and finally the Montreal Campaign from July to September 1760 which finally wrested Canada from France. At Quebec General James Wolfe is said to have granted the 60th the motto Celer et Audax (Swift and Bold). To reward and maintain their service and loyalty, Parliament passed the American Protestant Soldier Naturalization Act 1762 (2 Geo. 3. c. 25), which offered British naturalization to those officers, engineers and soldiers who had or would serve for two years, with certain conditions and on the model of the Plantation Act 1740.

These earlier engagements were conventional battles on the European model, but fighting during Pontiac's War in 1763 was of a very different character. The frontier war threatened the British control of North America. The new regiment at first lost several outlying garrisons such as Fort Michilimackinac, later a detachment fought under Bouquet's leadership at the victory of Bushy Run in August 1763.