After his honorable discharge from the Navy, Latimer found employment at Crosby & Halsted, a patent law firm. Starting as an office boy, he quickly learned drafting skills and became proficient in creating technical drawings for patent applications.

Latimer received his first patent for an improved railroad car water closet. This marked the beginning of his career as an inventor.

Latimer received another patent for an improvement in water closets, demonstrating his continued interest in improving sanitation technology.

Latimer joined the U.S. Electric Lighting Company, where he worked as a draftsman and eventually became a key member of the team developing carbon filament lamps.

Latimer received a patent for a process of manufacturing carbons, a critical component in the production of long-lasting light bulb filaments. This invention significantly improved the efficiency and affordability of electric lighting.

Latimer received a patent for an improved electric lamp, further solidifying his contributions to the field of electrical lighting.

Latimer joined the Edison Electric Light Company (later General Electric), working as a draftsman, expert witness in patent litigation, and instructor. He was the only African American member of 'Edison's Pioneers,' a group of early employees.

Latimer received a patent for a lock for hats, coats, and umbrellas, showcasing his diverse inventive capabilities beyond electrical lighting.

Latimer received a patent for a support for hanging clothes, demonstrating his continuous stream of innovative ideas.