Moss is taking up the role to support group managing director Margaret Johnson, following a spate of new-business wins. The role has not been filled since November 2003, when Justin Bairamian quit Leagas Delaney for a role at the BBC.
Moss joined Leo Burnett in 1993 and has held roles at Leo Burnett Mumbai as client service director, and in Mexico, where he was regional account director for Latin America.
In 2001, Moss moved back to London where he was appointed as the agency's head of account management, working primarily on the Procter & Gamble business.
Tim Delaney, CEO of Leagas Delaney, said: "Elliot has a rare combination -- international experience on one of the world's most impressive brands with great enthusiasm for the business. He's a great addition to our team in London."
Last week, Leagas Delaney was shortlisted alongside Mustoes for the BlackBerry creative account. The agency also revealed today that in the last week it has won the pitch on a global account, due to be announced shortly.
Business growth in the last 18 months includes the airline group Emirates, Swiss private banking group Pictet, Bacardi's Eristoff Vodka brand, Platinum Guild International, and Reebok.
"I relish the opportunity to work with one of the truly principled and creative agencies in the industry," Moss said.
In May of this year, Leagas Delaney was dropped from Twinings £4m creative account after only one year of working together and a high-profile TV campaign starring Stephen Fry.
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