He passed away at a Hertfordshire hospice last week, having suffered from the muscle-wasting condition for more than three years.
As the Publicis joint chief executive in the late 80s, he helped guide the agency through one of its most successful periods when it won an estimated £70 million-worth of new business.
But he will be best remembered for helping to launch Barker & Ralston with the creative David Barker in 1990. The agency stunned the industry by elbowing its way on to the pitch for the £35 million Abbey National business and winning it just ten days after opening.
Ralston had an extensive agency career that also included spells at Davidson Pearce and Grey. He is survived by his wife, Leslie, and their sons Ben, Thomas and David.
His funeral is held today (Thursday 5 June) at 11am at the Memorial Hall, Chorleywood, Hertfordshire. Donations may be made in his memory to the Motor Neurone Disease Association.