Seah returns to the industry after selling a popular Singapore bar he launched. A stint as creative director at DDB sibling Rapp Collins followed a time running local creative services shop Generator, an agency he founded.
Seah began his career at Saatchi & Saatchi New York in 1988 and has also worked at Saatchis in London.
"I've tried everything - working in New York and London, and I have also been the own boss of my own agency," said Seah.
"But an in-house creative director at Singapore's biggest media company is a whole new animal. We're set up to produce a better creative product, and hopefully agencies can depend on us. We're a tool that's working with them and for them - not against them."
MediaCorp announced it was restructuring its sales operations in November last year to offer integrated advertising packages.
MediaCorp's major brands include Today, Channel NewsAsia, FHM and Class 95FM.
The restructure was also seen as a move to boost revenues from the company's weaker performing divisions.