Eli has been used as an English Christian given name since the Protestant Reformation. A notable bearer was the American inventor of the cotton gin Eli Whitney (1765-1825).
After the Protestant Reformation it was occasionally used as a given name in the English-speaking world, and it became somewhat common in America due to the fame of the revolutionary Ethan Allen (1738-1789). It only became popular towards the end of the 20th century. It is the name of the main character in Edith Wharton's novel Ethan Frome (1911), about a man in love with his wife's cousin.
The name has been very common throughout the English-speaking world since end of the 20th century. In the United States it reached a high point in 2017, when it ranked as the fifth most popular name for boys.