The pair join the agency from Rapp, where they were creative group heads on the NSPCC and Cancer Research UK accounts.
Donovan and Leney have worked together for 12 years, including spells at Inferno, Wunderman and TBWA. They have won awards at Cannes, Campaign Direct and at the DMAs.
Steve Aldridge, the creative partner and chairman of PAA, said: "Richard and Jon are a rare find, they're strong across all media and have exceptional craft skills. I believe they will have an immediate impact as we continue to push our creative product on to a higher level."