Meade was commissioned a second lieutenant and served in the Seminole Wars in Florida. He was an artillery officer for a year before resigning in 1837 to become a civil engineer. He reentered the army in 1842 after having difficulty in finding jobs. Meade was a second lieutenant in the Corps of Topographical Engineers when the Mexican–American War broke out in 1846. He was then placed in charge of lighthouse construction and later, surveying the Great Lakes.