The competition will see various projects of national significance fighting it out for a grant of up to £50m, with the winning project being decided by public vote in early December.
Cake won the campaign following a competitive pitch against Cunning, Frank and Porter Novelli.
Director Davnet Doran will oversee the team of six people working on the project, which includes account manager Jodie Butt and senior account executive Laura Bonney.
Cake has started a national media relations campaign, with the aim of raising awareness of the contest as well as maximising the number of votes cast. The appointment follows a competitive pitch managed by the Central Office of Information.
The Big Lottery Fund, which is the largest of the National Lottery good cause distributors, rolls out close to £2m in grants every day to health, education, environment and charitable causes across the UK.