He will work as a contact between the agency and its most senior clients as well as helping its new-business drive.
Pringle is likely to devote two days per week to the agency, combining it with his work as an Advertising Standards Authority council member.
He will work with 23red on an exclusive basis, after undertaking not to work on assignments for other agencies.
Pringle had an extensive career before becoming the head of the IPA in 2001. He began as a graduate trainee at Ogilvy & Mather in 1973 and had spells at BMP, Abbott Mead Vickers BBDO and Leagas Delaney, as well as founding Madell Wilmot Pringle. He is also a former director of marketing at Saatchi & Saatchi.
23red's clients include Bacardi, for which it produced the "champions drink responsibly" campaign featuring Rafael Nadal. It also works on the Department of Health's Change4Life initiative.
Pringle worked with Jane Asscher, 23red's managing partner, on the IPA's Magic And Logic publication series.