According to Miles Young, regional chairman at Ogilvy, the pair will bring an Asian perspective to the global board as the network looks to the region for future growth.
"(The appointments) underline the importance of Asia to the company, an importance that is switching and increasing all the time. There are more initiatives and ideas emerging from Asia and exporting to other parts of the world," said Young.
Tham, a top creative talent, has won awards at major international award shows, including Gold at Cannes.
Issac, who joined Ogilvy in 1993, added geographic responsibility for all Ogilvy operations in Southeast Asia to his role four years ago.
He will also continue to oversee all aspects of Ogilvy's business in Singapore, in an interim capacity, following the sudden departure of Gerard Lim, who left the agency less than a year after taking the role of managing director in in the city.
Lim will return to Leo Burnett for a contract assignment looking at business development opportunities for both Burnett and its interactive agency.
"Given Gerard's in depth knowledge of the workings of almost everything to do with the advertising business here, I know this will be a fruitful re-union. We are delighted to have him back," said Leo Burnett managing director John O'Shea.
Both Lim and Issac declined to comment on the departure.
However, Issac noted that a new country head, in addition to a replacement for Lim, would be announced soon.
Lim was previously general manager at Burnett Singapore and has spent almost six years at the agency.
Additional reporting by Arun Sudhaman
Tham and Isaac join Ogilvy board to offer Asia insights
Ogilvy & Mather's Tham Khai Meng, regional creative director and co-chairman for Asia-Pacific, and Tim Issac, vice-chairman for Asia-Pacific and head of Southeast Asia, have been promoted to the agency's worldwide board.
