Priest will head a combined jury of more than 60 of the ad industry's top creatives, judging the best of British advertising across media channels.
The awards open for entries next week and the deadline for submissions is 17 June. The awards ceremony will be held at the Grosvenor House in London on 26 October.
Priest said: "Almost overnight, the Big Awards have established themselves as a key date in the UK advertising industry's calendar.
"Both the judging and the night itself are invigorating affairs: the very best digital, television, print and outdoor talent the country has to offer, gathered together, battling it out for big prizes. It's something I'm delighted to be part of."
Last year's gold winners included Abbott Mead Vickers BBDO's "choose a different ending" campaign for the Metropolitan Police, Publicis' "start thinking soldier" campaign for the British Army, M&C Saatchi's "the last place ..." work for Dixons and Wieden & Kennedy's "write the future" for Nike.
Previous jury chairmen for the Big Awards were Nigel Bogle of Bartle Bogle Hegarty in 2008, 101's Laurence Green in 2009 and Damon Collins of Rainey Kelly Campell Roalfe/Y&R in 2010.
For full details on how to enter the Big Awards, visit campaignbigawards.com.