Danielle Bassil, who joined the agency in October last year as chief operating officer, has been promoted to chief executive of Digitas UK.
Islip, who has been with the agency for a decade, is credited with creating the Publicis Groupe customer engagement hub in 2016 and leading the relaunch of the Digitas brand in the UK.
During his tenure, Publicis also moved Digitas from Publicis.Sapient to Publicis Media and appointed a new global brand president, Michael Kahn, to lead it.
"The past couple of years has seen some huge changes for the agency but now we're comfortably settled into the Publicis Media family, both in the UK and globally, it's the right time for me to do something else. Digitas is a brilliant agency and it’s been an honour to be part of its story for the past 10 years," Islip said.
Bassil, who moves into her new role with immediate effect, will be responsible for developing and executing the agency’s strategic vision and raising its creative output. She is expected to name a new chief operating officer in the coming weeks.
With more than 20 years experience, Bassil joined Digitas from J Walter Thompson London where she was a managing partner for nearly three years. Prior to that she had held senior roles at Possible, Grey and VCCP.
After thanking Islip for his contributions, Sue Frogley, chief executive of Publicis Media UK, added: "Dani is a rare talent with a wealth of experience, energy and ideas and I am delighted to welcome her onto my leadership team. With Dani at the helm I know that the Digitas team will go forward into a new era of creativity and growth."