He served as an officer in the French and Indian War, primarily in upstate New York, near Fort Crailo.

Their appearance when entering West Albany, with feathers in their hats and unpolished clothing, caused British surgeon Dr. Shuckburgh to write verses mocking Fitch and his men as "Yankee Doodles and Macaronies".

Fitch had the rank of Senior Colonel and was in command of sixteen regiments by the time that he had left the service three years later.

Norwalk historian, Gloria Stewart claims that eighteenth century documents available from the Connecticut state archives dispute the Yankee Doodle identity.

[6] In addition, no Thomas Fitch from Norwalk appears as a colonel in the Rolls of Connecticut Men in the French and Indian War, 1755-1762.