Chenault, who is of African American heritage, was born in Mineola, New York, the son of a dentist and dental hygienist.

The elder Chenault passed the New York State dental exam with the highest score ever recorded as of January 2014.

[6] Kenneth Chenault attended the Waldorf School of Garden City,[7] where he was senior class president.

Chenault began his career as an associate at the law firm Rogers & Wells (1977–1979) in New York City, and as a consultant for Bain & Company (1979–1981).

[29][30] On November 15, 2010, Old North Foundation recognized Chenault with its Third Lantern Award for individual commitment and dedication to public service.

[31] Chenault and wife, Kathryn, are founding donors to the Art for Justice Fund, which aims to reduce prison populations and strengthen employment opportunities for those leaving.

[8][33] On February 6, 2017, Chenault was named chair of the advisory council for the Smithsonian's National Museum of African American History and Culture.

[37] In October 2024, it was reported that Chenault is a potential choice for United States Secretary of the Treasury should Harris win in the upcoming presidential election.