Chalkley's former partner, Chris Wright, left the agency to attend business school last September.
Whiston joined HHCL & Partners in 1989, a year after it launched, and stayed at the agency for eight years. In 1995, after two years as the creative director, she co-founded its fast-turnaround sister shop, The Advertising Brasserie, sharing the position of creative director with her fellow ex-HHCL staffer Dave Shelton.
Whiston's creative credits include the "fourth emergency service" campaign for the Automobile Association, the Ronseal "it does exactly what it says on the tin
campaign, the LineOne campaign featuring Malcolm MacDowell and the Harry Enfield Cholmondley-Warner campaign for Mercury Telecommunications.
Last April, Whiston left the Brasserie - which closed down last July citing poor trading conditions - and has since been working on a freelance basis. At St Luke's she has already begun working on campaigns for British Telecom, COI Communications and AMP, the Australian finance account won by the agency earlier this year. She is also likely to work across various other pieces of agency business.
Whiston said: "I wanted to be hands-on again, writing major campaigns for large clients. Jules is very exciting to work with. And St Luke's is a progressive agency, which is my thing completely."
Young added: "Our policy at St Luke's is to front accounts with top-level senior creatives. We are delighted that a writer and thinker of Liz's calibre is joining us."