Lindsay Turner is leaving her post as chief executive of Spark Foundry UK at the end of May.
She will be succeeded by Pete Edwards, who joined the business as chief client officer in 2019. He will report to Sue Frogley, chief executive of Publicis Media UK.
Turner became chief executive of Blue 449 and Spark Foundry in April last year, after the shock departure of Simon Davis.
She was previously managing director of Blue 449 and had worked at the agency since 2011, when it was known as Walker Media.
During her tenure, Turner oversaw the Blue 449 and Spark Foundry merger, which was announced in December.
Spark Foundry has been shortlisted for four awards at the 2020 Campaign Media Awards, including Agency Team of the Year for Platform GSK.
Turner said: "I have had the opportunity to work with some amazing people and do some great work over my nine years with the agency. After leading a successful merger, navigating a year of change for the organisation and emerging even stronger, now felt like the right time for me to step down. I’ll be leaving with some great memories and experiences under my belt and I’m ready for the next challenge."
Before joining Publicis Media, Edwards was chief executive of Engine Media for more than two years. Between 2009 and 2011, he was director of strategy at Engine, including consolidating its media offering to launch Engine Media in 2017. He co-founded Edwards Groom and Saunders in 2006 and sold it to Engine three years later.
Frogley said: "In Pete, we have someone who knows the business and our clients well, who has a deep understanding of the marketplace, and a wealth of leadership experience and track record to take the agency from strength to strength.
"I’d like to thank Lindsay for everything she has done since joining the agency in 2011, which she leaves in excellent shape with a strong leadership team in place. We are all sad to see Lindsay go and will miss her energy and passion, but we respect her decision and wish her the very best for the future."
Edwards added: "Over the past year, we brought together two successful agencies to give our clients the best of both worlds. With the right talent, culture and proposition now in place, I feel incredibly proud to have the chance to lead this agency going forward."