The famous military leader who started the French and Indian War was a young Major George Washington. In 1754, Washington's surprise attack on a small French force at Jumonville Glen and his subsequent surrender at the Battle of Fort Necessity were key early events that sparked the war between British and French colonial forces.

However, the leading French military commander during the French and Indian War was Lieutenant-General Louis-Joseph de Montcalm, who was sent by King Louis XV to defend New France from the British. Montcalm is well known for his role defending French territories and fighting key battles until his death in 1759.

In summary:

• George Washington, then a British colonial officer, initiated the conflict that became the French and Indian War.
• Louis-Joseph de Montcalm was the prominent French military leader defending New France during the war.

Thus, George Washington is credited with starting the war through his initial military actions, while Montcalm was the major French commander during the conflict.