Johnston leaves Carlson after 11 years, where she was on the management board and oversaw financial, business and client management across a range of high-profile accounts.
Her brief at Tequila\ sees her take up responsibility for developing client service best practice. She will identify areas where the agency can improve its client relationships, ensuring that it is best placed to respond to increasing client needs, while strengthening the agency's CRM expertise.
The appointment continues the below-the-line network's aggressive expansion plans. In the last year, Tequila\London has appointed more than 20 new staff on the back of a number of new-business wins including Barclays, Kraft and Wines of Chile.
Tequila\London CEO Paul Biggins said: "Louise comes with high-level CRM expertise and client servicing skills, which will be instrumental in reinforcing our position as a top five agency. Her appointment also reflects the continued growth and investment in talent that has been a hallmark of the agency since its inception 10 years ago."
The Omnicom-owned Tequila\ network has 36 offices in 25 countries, including two in the UK with its London and Manchester agencies.
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