The cause of death is unknown, according to the spokesman.
A native of the U.K., Mr. Gault, 45, spent the bulk of his career at McCann-Erickson after studying at Cambridge.
Beginning as a management trainee, Mr. Gault served in numerous managerial roles during his career: He was director of worldwide accounts in London, and later rose to lead McCann-Erickson Japan, one of the agency's largest offices.
In 1996, he moved to Tokyo and became managing director; two years later, he was named chairman of the agency and area director of the Asia/Pacific region. In 1999, he became director of worldwide accounts at McCann-Erickson Worldwide, overseeing roughly 20 accounts.
Most recently, Mr. Gault moved to New York, where he worked in the agency's headquarters. There, he oversaw the operations of McCann's North American network of full-service agencies and worked directly with key North American clients.
He also served as a member of McCann's worldwide board and of the McCann-Erickson WorldGroup board.
He is survived by a wife and two children.