They will take over from Shaun Moran, who left the agency to join Lida in March.
Todd, a copywriter, and Snoxell, an art director, joined PAA when the agency acquired DS-J three months ago.
The pair will take on the day-to-day control of the creative department, working across PAA's portfolio of clients including Visit Wales, Lexus and the BBC. They will report to Steve Aldridge, a creative partner at the agency.
Todd, who has won 16 Direct Marketing Association golds, a Cannes Lion and several Campaign Direct awards, began his career at GGT, before spending time at EHS, Craik Jones and WWAV Rapp Collins.
In 2002, he left WWAV to set up DS-J with the founding partners Edmund Smiley-Jones, Mark Davidson and Snoxell. Before founding DS-J, Snoxell held the role of creative director at the digital agency Zinc. His career also includes a spell as a creative director at EHS Brann.
Aldridge said: "Todd is one of the most unsung talents of our industry and Snoxell is a genuine creative thinker."