Thomas Edison was born on February 11, 1847 in Milan, Ohio, to Samuel Ogden Edison, Jr. and Nancy Matthews Elliott (1810-1871). Thomas was their seventh child. Edison had a late start in his schooling due to childhood illness. His mind often wandered and his teacher Reverend Engle was overheard calling him "addled". This ended Edison's three months of formal schooling.

Partially deaf since adolescence, he became a telegraph operator. Edison's deafness aided him as it blocked out noises and prevented Edison from hearing the telegrapher sitting next to him.

Thomas Edison began his career as an inventor in Newark, New Jersey, with the automatic repeater and other improved telegraphic devices, but the invention which first gained Edison fame was the phonograph in 1877. This accomplishment was so unexpected by the public at large as to appear almost magical. Edison became known as "The Wizard of Menlo Park, New Jersey" where he lived. His first phonograph recorded on tinfoil cylinders that had low sound quality and destroyed the track during replay so that one could listen only once. In the 1880s, a redesigned model using wax-coated cardboard cylinders was produced at the Bell Laboratory by Chichester Bell and Charles Tainter. This was one reason that Thomas Edison continued work on his own "Perfected Phonograph".

In December 1879 he began his duties as laboratory assistant to Thomas Edison at Menlo Park. He assisted in experiments on the telephone, phonograph, electric railway, ore separator, electric lighting, and other developing inventions. However, he worked primarily on the incandescent electric lamp and was put in charge of tests and records on that device.

Many of his inventions were not completely original, but improvements which allowed for mass production. For example, contrary to public perception, Edison did not invent the electric light bulb.