Rochambeau was born July 1, 1725, in Orléanais, France. After the death of his elder brother, he entered a cavalry regiment and served in Bohemia, Bavaria, and on the Rhine during the War of the Austrian Succession. By 1747, he had attained the rank of colonel.
In 1780, Rochambeau was appointed commander of land forces as part of the project code-named Expédition Particulière. He was given the rank of lieutenant general in command of 7,000 French troops and sent to join the Continental Army under George Washington during the American Revolutionary War.
In July 1781, Rochambeau and his troops left Rhode Island and marched across Connecticut to join Washington on the Hudson River in Mount Kisco, New York. The Odell farm served as Rochambeau's headquarters from 6 July to 18 August 1781.
Washington and Rochambeau then marched their combined forces to the Siege of Yorktown and the Battle of the Chesapeake. On 22 September, they combined with the Marquis de Lafayette's troops and forced Lord Cornwallis to surrender on 19 October.
The Congress of the Confederation presented Rochambeau with two cannons taken from the British in recognition of his service. He returned them to Vendôme, and they were requisitioned in 1792.