After studying photography in Paris, Johnson-Hill began her career working in the fashion department of French Vogue and as a fashion assistant for Vogue Italia. She then relocated to New York, working as an agent and production manager for photographer Pamela Hanson, followed by a job as bookings editor during the launch of Russian Vogue. Her other professional endeavours include producing an in-house film starring Chloe Sevigny for Ritz Fine Jewellery in 2005, appearing on ITV2 as a fashion consultant and co-producing the book and exhibition The Speed of Life.
Johnson-Hill is currently owner of The Production Club, a pioneering photographic stills production company. Clients include Balenciaga, Tom Ford, Hugo Boss, H&M, Burberry, Dior and Jil Sander. She is also contributing European editor of Interview magazine.