Jones, who is one of adland's most high-profile figures, will retain close ties with the agency search and selection operation, but only on a part-time basis.
He said: "I have had 12 wonderful years working with some fantastic agencies, clients and people. Twelve years is, however, a very long time to do such a demanding job and I have come to the stage where I feel the need to take a step back and look at some different challenges."
Jones, a former new-business director at JWT, will stay on until the end of the year. His day-to-day responsibilities will then be assumed by Paul Phillips, the AAR's managing director.