Lam will be based in Bangkok and lead the Procter & Gamble shampoo brand's marketing communications in Thailand, the Philippines, Malaysia, Indonesia, Vietnam and India.
Lam previously worked on P&G brands during an eight-year stint with Burnett in Kuala Lumpur, which ended in early January, 2003.
"I've worked on Kellogg's and P&G, so I'm familiar with Rejoice, SKII and Vidal Sassoon," said Lam, who moved to Burnett after a year-and-a-half at Euro RSCG.
His appointment comes as P&G sharpens its brand strategy for Rejoice.
The company has been actively positioning Rejoice as the gold standard which can deliver hair care treatments such as hot oil and rebonding in a shampoo bottle.