Curran, one of the team working on the Bacardi brief won by Synergy last year, takes on the role of global sport director with the spirits giant at the end of next month.
The move will see Curran seek to develop the group’s numerous links with sports, which include Martini’s sponsorship of Williams in Formula 1.
Curran, who joined Synergy in 1999, said: "I'm joining Bacardi Global Brands in the new role of global sport director with the remit to work with the brands and markets in maximising sport as a consumer engagement platform.
"Based within the Global Experiences & Engagement team in Dorset Square, it's a hugely exciting new role."
Synergy CEO Tim Crow revealed that Curran would not be directly replaced, because, he said, the agency "had so much strength and depth".
He went on to praise his longstanding colleague, stating: "Dom’s been fundamental to the growth of the business and is much loved. I’d say we’ll miss him, but we’re all rather looking forward to him becoming a client."