Atomic said Bentley will also focus on strategy, planning and new business. She was a client of Atomic's in her role at Pernod Ricard UK.
Bentley's previous positions include senior PR & communications manager at Treasury Wine Estates EMEA, associate director at Trimedia (now Grayling) and senior account manager at Touch PR. Bentley has worked for companies including Coca-Cola, Nescafé, Diageo, William Grant & Sons and First Drinks.
Atomic MD Daniel Cohen said: "Sarah’s knowledge of the drinks sector and her experience not only as our client previously, but across the industry will only serve to boost our own offering for our clients in the consumer space."
The agency's drinks clients include Campo Viejo, Brancott Estate, Jacob’s Creek and Graffigna, as well as The Glenlivet.
Bentley's appointment takes Atomic up to 18 members of staff.