The global director at Diageo discusses her career trajectory, favourite brand campaigns and the power of Guinness ads Diageo’s Grainne Wafer has always been driven by a love of writing and storytelling — a passion that once had her set on becoming a journalist. 29 years into her award‑winning career with the global drinks giant, she has held a range of senior roles and now serves as global category director for Beer, Vodka, Liqueurs and Convenience.