The agency was forced to re-pitch for the business in early January against Doner Cardwell Hawkins and the direct marketing agency Joshua.
Each agency was asked to create a number of TV scripts promoting a range of possible new product launches that Florette is considering for the UK market.
Hooper Galton was initially dropped from the race, leaving a two-way shoot-out between the remaining agencies. However, the salad brand, which is owned by the French company Soleco, made a U-turn on its decision by re-appointing the incumbent at the last minute.
The agency was originally appointed to the account in February 2004, following a three-way pitch against two undisclosed agencies.
Since then, the company has steadily increased its marketing spend, as it expands its business and launches new product lines.
Its latest innovation is pre-packed steamed vegetables, which Florette launched in December last year. The launch was backed by a television campaign created by Hooper Galton.
Oliver Lewis-Barclay, a managing partner at Hooper Galton, said: "Re-pitches seem to be a hazard of modern life these days.
"We felt we had unfinished business with the Florette brand - not least because it was barely a brand when we first started working on it - so we're delighted to have come out on top."