Lloyd joins from Momentum, where she headed up the Manchester new-business team and introduced a range of new clients to the agency, including Carlsberg and Reebok.
She worked across a range of disciplines and managed her first new-business team at the age of 25.
Lloyd brings TBWA experience of UK and international business, wins with clients such as Procter & Gamble, Arcadia Group and Sainsbury's.
Lloyd said: "I was attracted by the no-nonsense, highly creative and ambitious approach here. When the opportunity presented itself, I simply had to say yes."
Robert Harwood-Matthews, CEO of TBWA\Manchester, said: "We love Keira and think she'll be a great matchmaker for the agency and clients."
TBWA\Manchester's clients include GHD, Jessops, PZ Cussons, Corwn Paints, Nissan, Wickes and AG Barr.