He joins from New Zealand's largest banking group, ANZ, where he worked on the bank's direct marketing business.
Previously, Strather spent eight years in Malaysia, where he set up Grey Direct.
Strather will report to Jean-Paul Burge, the BBDO Singapore managing director.
Burge said: "Rod is one of those rare individuals who has successfully straddled both the agency and client side. He has a keen entrepreneurial spirit and will complement the momentum we have built in both BBDO and Proximity."