Karen began her media career in 1993 at CIA MediaNetwork (now known as Wavemaker), working across a range of media performance accounts. Karen continued her career by joining Zenith Media in 1995 working on the prestigious BT account. Karen was quickly head-hunted by The Media Business Group.

In October 1999 Karen was promoted to the Board of Directors of the newly merged MediaCom and The Media Business Group Board. In January 2003, Karen moved from the Business Director role that she had held for so long to become the Marketing Director of MediaCom.

In 2008, Karen became MediaCom’s Chief Operations Officer for EMEA. Priority markets included Russia, Turkey, France, Spain, Portugal, Poland, Czech Republic and South Africa. After 3 years strengthening the EMEA network, during which time MediaCom moved from the 5th to 3rd largest EMEA network media agency, Karen was promoted to CEO of the UK Office in January 2011, running over £1.3bn of media billings and leading over 1,200 people in 5 UK locations.

MediaCom UK is the largest media agency in the UK with a range of diverse clients, such as Sky, Tesco, Coca Cola, Cancer Research UK, DFS, NBC Universal and Mars. MediaCom U.K represents Modern Britain with offices in London, Manchester, Birmingham, Leeds, Edinburgh and Dublin. During Karen’s tenure as CEO the UK business won over £790 million of new business. (2011 -2015 inclusive)

In January 2016 after serving as CEO for 5 years, Karen was promoted to Chairwoman of MediaCom UK & Ireland and is closely linked with clients such as Tesco, Coca-Cola and Sky. In the role as Chairwoman, one of Karen’s many focuses was to support the continued growth and evolution of the regional UK offices which totalled 350 staff and had regional combined billings of £385 million. In January 2018, Karen took on a newly created role as the first UK Country Manager for WPP, the world’s largest communications network, overseeing 10,000 people across several well-known operating brands such as Ogilvy, Grey, H&K, VMLY&R and Wunderman Thompson. In this role Karen is responsible for delivering growth in WPP’s 2nd largest market, with revenue of $2 billion. Her focus is on developing customer experience, commerce strategies, marketing technology and relevant real-world communications for WPP clients.

In 2019 Karen was appointed a Non-Executive Director of the UK Cabinet Office. Karen was appointed as CEO of GroupM U.K, the world’s leading media investment company, in April 2020 – an additional role to her WPP UK Country Manager responsibilities. In November 2020 Karen featured in one of the Top 100 Great Black Britons, and in December 2021 was chosen to feature in the book; The Female Lead.