Henry Bouquet was born around 1719 at Rolle, in the French-speaking portion of the Republic of Bern, now Switzerland. He was the son of Isaac Bouquet, an innkeeper, and Madeleine Rolaz. Although not born into the aristocracy, he grew up in a region that supplied trained soldiers to armies throughout Europe. Swiss military service abroad offered ambitious young men employment, education, and social advancement. Bouquet became fluent in several languages and developed the polished manners, mathematical interests, and administrative habits valued in an eighteenth-century officer.

He entered military service while young, probably first in a regiment maintained by the Dutch Republic. By the 1740s he was serving the king of Sardinia during the War of the Austrian Succession. Campaigning in northern Italy exposed him to mountain warfare, fortifications, reconnaissance, and the movement of troops through difficult terrain. He rose through merit in foreign service rather than through the British system of family patronage and purchased commissions.

After the war Bouquet entered the service of the Dutch and became acquainted with other Swiss Protestant officers. His career changed when Britain decided to raise the Royal American Regiment, formally the 60th Regiment of Foot, for warfare in North America. The regiment sought officers who spoke German and French and who could work with immigrant recruits unfamiliar with English military life. Bouquet received a lieutenant colonel’s commission in 1756.

Before taking the field, he helped organize, discipline, and train the new regiment. His European background made him receptive to lighter equipment, dispersed formations, aimed fire, and the use of cover—adaptations increasingly recognized as necessary in wooded country. He also proved meticulous about supply, camp sanitation, engineering, and written orders. By the time he joined British operations in Pennsylvania, Bouquet was already a mature professional whose Swiss origins and varied continental service distinguished him from most officers in the British Army.