He will oversee the rigorous DMA judging process, which involves more than 200 industry experts from client companies, suppliers and agencies.
He will also lead the final Grand Prix judging process, during which an overall champion is selected from among the Gold winners.
Smith said: "I know just how much a DMA Award is valued by the winners. I’m really looking forward to engaging with the wealth of exciting creative work which always emerges during the DMA Awards."
Previous chairs of judges have included Rory Sutherland, vice-chair of Ogilvy Group UK, and film producer Lord Puttnam.
Mike Colling, chair of the DMA Awards Committee, said: "It’s a great honour that Lord Smith has agreed to chair the DMA Awards judging. His outstanding insight and industry expertise mean that he is ideally positioned to guide and advise the judging panel."
The winners of the 2011 DMAs will be announced at the Awards Presentation Ball to be held at Old Billingsgate in the City of London on 7 December.
Agencies and brands have until Friday (9 September) to submit their entries.
Entries will be judged in October. Each campaign is judged individually and then by group discussion on three key criteria: strategy, creativity and results.
For the first time, the 2011 DMA Awards are sponsored by TNT Post.