The campaign, created on a budget of £2.5m by Abbott Mead Vickers BBDO London, aimed to keep crisps at the front of consumers' minds as a lunchtime snack, and led to revenue growth of 26%, exceeding the 15% growth target.
Procter & Gamble won two Creative Effectiveness Lions, with McDonald's, Mars Chocolate and TVNZ, a New Zealand TV programme, picking up one Lion apiece.
The Walkers campaign saw the town of Sandwich transformed with Formula 1 driver Jenson Button as the the town taxi driver, and Chelsea striker Frank Lampard coaching the local football team.
Cannes Lions organisers Emap introduced the category this year as part of its efforts to boost the business profile of the event, and to recognise the actual business impact that creative communication can have.
To enter the new creative effectiveness category, ads had to have won a Lion or been shortlisted at last year's festival. Walkers' Sandwich campaign, a recent Marketing Society Awards gold winner, had scooped several Lions in 2010.
The jury, which featured clients including Mathilde Delhoume-Debreu, a director at P&G Asia and EMEA, and LG's global communications director Kenneth Hong, gave a 50% weighting to effectiveness, and 25% each to strategy and the creative idea.
The UK-dominated shortlist for the new effectiveness category proved controversial among the large international contingent of delegates and press.
TBWA chairman Jean-Marie Dru, president of the Creative Effectiveness Lions jury, conceded that UK agencies had an advantage in the category because of their familiarity with the demanding IPA Effectiveness awards.
Dru told journalists after the shortlist was announced: "Because of the IPA awards in the UK, we believe the UK agencies have been slightly advantaged by the process because they knew how to enter this category in a very strong way."
The final night of the Cannes Lions International Festival of Creativity also featured the Film, Film Craft and Titanium and Integrated Lions awards ceremonies.
Nike's 'Write the Future' campaign, by Wieden+Kennedy Amsterdam, won the Film Grand Prix.