A unique corps of 600 frontiersmen who successfully adapted Indian techniques to their fighting, Rogers's Rangers emphasized self-sufficiency, courage, stealth, and methods of camouflage. Conducting numerous raids, scouting enemy positions, and capturing prisoners, Rogers's Rangers gained a reputation as the most colourful unit in the British-American army.

During the French and Indian War, Rogers took part in Gen. James Wolfe (Wolfe, James)'s expedition against Quebec and in the Montreal campaign of 1760. Afterward he was sent by Gen. Jeffrey Amherst (Amherst, Jeffery Amherst, 1st Baron) to take possession of the northwestern posts, including Detroit. Rogers was again in the West in 1763, during Pontiac's War, and he participated in the Battle of Bloody Bridge. Soon after, he went to England and in 1765 published in London a Concise Account of North America and his Journals of service in the French and Indian War.

Rogers proposed to King George III that he lead an overland expedition from the Mississippi River to the Pacific Ocean. Although Rogers's offer was refused, he was given command of the northwest post of Michilimackinac. From there in 1766 he sent out on his own initiative the first English expedition to explore the upper Mississippi and Great Lakes region, but it failed to penetrate to the Pacific as intended. Rogers's ambitions caused him to be tried for treason, but he was acquitted. He again went to England to retrieve his fortune but was unsuccessful. During the American Revolution he went to America but was regarded as a loyalist spy. He then openly joined the British and organized and commanded the Queen's Rangers, which saw service in operations around New York City. Later he organized the King's Rangers, but the command was taken by his brother, James Rogers, and Robert Rogers returned to England, where he lived his final years in obscurity.