The new scheme, called the creative partner system, will see senior creatives taking individual responsibility for specific accounts, with the aim of forging better relationships between clients and the creative department.
Craigen will oversee the process in addition to heading the Volkswagen, Unilever, Capital One and Johnson & Johnson accounts.
The creatives Will Awdry, Andrew Fraser, Justin Tindall and Adam Tucker have each been promoted to creative partner level and have been handed their own groups of clients to manage.
Awdry will have responsibility for international accounts, including Dell and Nestle Purina, as well as the Arla, Thomson and COI Communications businesses, while Fraser will head The Guardian, Philips, PepsiCo, Exxon Mobil and Wyeth.
Tindall, who is currently the head of art, and his partner, Tucker, will take joint responsibility for the Harvey Nichols, Hovis, Kwik-Fit, Meat and Livestock Commission and Speedo accounts.
Paul Hammersley, DDB London's chairman and chief executive, said: "Jeremy's promotion is a timely recognition of all that he achieved. His plans for the department are part of broader ideas to better align the agency with its clients' real business needs."
Craigen added: "The better we know our clients' business, and the better they know us, the better the work will be. Will, Andrew, Justin and Adam are all more than capable of making this a success."