Born in 1695 as the son of Major-General Edward Braddock of the Coldstream Guards, Braddock embarked on a military career, following his father's path into the British army. At the tender age of 15, he received his commission as ensign in his father's regiment on 11 October 1710, subsequently advancing to lieutenant of the Grenadier Company in 1716. Braddock's ascent through the ranks continued steadily. At 41, he attained the rank of captain in 1736, followed by promotion to major in 1743 and lieutenant colonel in November 1745.

His military service included participation in the Siege of Bergen op Zoom in 1747. On 17 February 1753, Braddock assumed the prestigious role of colonel of the 14th Regiment of Foot, and the subsequent year witnessed his promotion to major-general.
Appointed to lead British forces against the French in America, General Braddock arrived in Hampton, Virginia, with two regiments of British regulars on 20 February 1755. Following discussions with colonial governors at the Congress of Alexandria on 14 April, Braddock committed to aggressive actions against the French, coordinating attacks on multiple fronts: including General William Johnson at Fort Saint-Frédéric, Colonel Robert Monckton at Fort Beausejour, and Braddock himself leading an expedition against Fort Duquesne (now Pittsburgh) at the Forks of the Ohio River.

Despite facing administrative hurdles and resource shortages promised by the colonials, Braddock's expedition eventually mobilised with a select column, including volunteer officer George Washington. Crossing the Monongahela River on 9 July 1755, Braddock's forces encountered a joint Indian and French resistance from Fort Duquesne. While initial musket exchanges favoured the British, the enemy swiftly outmanoeuvred them, subjecting Braddock's troops to devastating crossfire. Braddock, fatally wounded during the engagement, succumbed to his injuries on 13 July.

The circumstances surrounding Braddock's demise remain debated. An article in The Roanoke Times from 1951 suggests he was mistakenly shot by an American soldier named Benjamin Bolling, prompting George Washington to assume command and orchestrate a retreat, purportedly sparing American lives caught in the crossfire.

Washington, along with Colonel Nicholas Meriwether, carried Braddock from the battlefield. Before his death, Braddock entrusted Washington with his ceremonial sash and pistols, which Washington kept throughout his life, eventually displaying the sash at Mount Vernon, his estate on the Potomac River.

Braddock's burial occurred near Great Meadows, with his grave intentionally obscured by wagons to prevent desecration by Native American forces. George Washington officiated at the burial due to the chaplain's incapacitation.