Born free on the Ontario shore of Lake Erie to parents who fled enslavement in Kentucky, he traveled to the United States as a young child when his family returned in 1847, becoming a U.S. resident and citizen.

Similar automatic oilers had been patented previously; one is the displacement lubricator, which had already attained widespread use and whose technological descendants continued to be widely used into the 20th century.

He continued to invent until late in life, obtaining as many as 57 patents; most related to lubrication, but others also included a folding ironing board and a lawn sprinkler.

Lacking the capital with which to manufacture his lubricators in large numbers, he usually assigned his patent rights to his employers or sold them to investors.

[11] This popular expression, typically meaning the real thing, has been attributed to Elijah McCoy's oil-drip cup invention.

One theory is that railroad engineers looking to avoid inferior copies would request it by name,[12] and inquire if a locomotive was fitted with "the real McCoy system".

"[16] Other possibilities for its origin have been proposed, including it being a corruption of the Scottish name "Reay Mackay"[17] and while it has undoubtedly been applied as an epithet to many other McCoys, its association with Elijah has become iconic in American parlance.