Bernardo O'Higgins, a member of the O'Higgins family, was born in the Chilean city of Chillán in 1778, the illegitimate son of Ambrosio O'Higgins, 1st Marquis of Osorno, a Spanish officer born in County Sligo, Ireland, who became governor of Chile and later viceroy of Peru. His mother was Isabel Riquelme, a prominent local; the daughter of Don Simón Riquelme y Goycolea, a member of the Chillán Cabildo, or council.
O'Higgins spent his early years with his mother's family in central-southern Chile and was never openly acknowledged by his father, and later he lived with the Albano family, who were his father's commercial partners, in Talca. At age 15, O'Higgins was sent to Lima by his father. He had a distant relationship with Ambrosio, who supported him financially and was concerned with his education, but the two never met in person. At the time of his son's birth, Ambrosio was only a junior military officer. Two years later, Isabel married Don Félix Rodríguez, a friend of her father. O'Higgins used his mother's surname until the death of his father in 1801.
Bernardo's father continued his professional rise and became Viceroy of Peru; at seventeen Bernardo O'Higgins was sent to London to complete his studies. There, studying history and the arts, O'Higgins became acquainted with American ideas of independence and developed a sense of nationalist pride. He met Francisco de Miranda, a Venezuelan idealist and believer in independence, and joined a Masonic Lodge established by Miranda, dedicated to achieving the independence of Latin America.
In 1798 O'Higgins went to Spain from Great Britain, his return to the Americas delayed by the French Revolutionary Wars. His father died in 1801, leaving O'Higgins a large piece of land, the Hacienda Las Canteras, near the Chilean city of Los Ángeles. O'Higgins returned to Chile in 1802, adopted his biological father's surname, and began life as a gentleman farmer. In 1806, he was appointed to the cabildo as the representative of Laja. In 1808 Napoleon took control of Spain, triggering a sequence of events in South America. In Chile, the commercial and political elite decided to form an autonomous government to rule in the name of the imprisoned king Ferdinand VII; this was to be one of the first in a number of steps toward national independence, in which O'Higgins would play a leading role.