He lost a lengthy battle with declining health at the age of 79 in London's Royal Free Hospital, where he had been taken from his Hertfordshire home, on Wednesday last week.
This week, tributes poured in for a shy and modest man who perpetually shunned the limelight but established the environment that allowed a new breed of agency creatives to thrive.
Charles Saatchi, Sir Alan Parker, Lord Puttnam, Ross Cramer and Michael Peters all owe their successful breaks into the business to Millward.
Although credited with the idea of using Bach's Air on a G String for the Hamlet campaign, Millward was not associated with a body of creative work of his own.
Instead, the blunt-speaking Yorkshireman's genius lay in identifying burgeoning creative talent and cajoling it into producing outstanding work.
In doing so, he transformed CDP into Britain's most creatively potent agency of the 60s and 70s with a string of mould-breaking executions.
"People whose reputation is built on the brilliant campaigns they did at CDP tend to forget that some of what they did was rubbish," Sir Frank Lowe, the one-time CDP managing director, said.
"Colin's achievement was in putting all their rubbish where it belonged - in the bin."
A one-time art student, Millward began his agency career in the 50s at the then Colman Prentice & Varley. When John Pearce, CPV's joint managing director, left to found CDP in 1960, Millward went with him.
It was there that Millward became the catalyst for a new kind of well-crafted and gently humorous advertising.
Although the output was distinctly British, it was profoundly influenced in its use of typography, photography and irreverent language by the ideas of Bill Bernbach, which Millward picked up during many visits to New York.
Millward's reign at CDP also set the trend for putting creativity at the heart of agency activity.
Not surprisingly, his passion spawned many apocryphal stories.
One of the most memorable concerned an account man who told him that Harveys didn't like the agency's latest ads. "Well lad," Millward replied, "off you go back to Bristol and tell them we do the ads and they make the sherry."
At the same time, he led the way in fighting for the budgets with which to employ outstanding creatives, photographers and directors. In 1976, D&AD honoured him with its first ever President's Award.
The following year, he quit CDP, the result of what was said to have become his disillusionment with agency politics. He never worked in advertising again.
Millward's funeral, to be attended only by his family and close friends, is being held this Friday at Mary the Virgin Church, Monken Hadley, near Barnet, at 1pm. A memorial service is planned for the autumn.
"So many of us owe Colin Millward so much. He taught us how to see, think and try harder. His standards were higher than anyone's in advertising, before or since."
Sir Alan Parker, film director
"Without Colin Millward, I would still be delivering groceries in Willesden."
"Colin brought a quality of art direction to UK ads which had never been seen before. Such was the quality of work for Hamlet and Benson & Hedges that you could run the ads today and they wouldn't look old-fashioned."
Tony Brignull, retired copywriter
"During his time, Colin was the most effective creative director in London because of the way he got good people around him. When he criticised their work it was with the knowledge that he knew he was right."
John Ritchie, former CDP deputy chairman
"Colin was the father of UK creative advertising. He was a true creative leader and an astute talent spotter. He had clarity of vision and a high level of confidence in his judgment."
Robin Wight, chairman, WCRS
"The Colin Millward I knew was a craftsman with golden hands in all he did. Direct and accessible, modest and wise, he suffered no fools. I will miss him."
Elliott Erwitt, photographer.