Kaess began in 1977 at Doyle Dane Bernbach, which was later renamed DDB. He left for a vice president/management supervisor position at Jordan, McGrath, Case & Taylor, then went to New World Entertainment, where he was responsible for the Emmy Award-winning Muppet Babies.
He ran the Los Angeles and New York offices before becoming worldwide president in 1999 and chief executive officer in 2001.
He was the first executive to serve two consecutive terms as head of the American Association of Advertising Agencies.
He died at his home in Westport, Connecticut, aged 51, of cancer.