Jon O’Donnell, managing director of ESI Commercial, is leaving the business after 11 years.
He is planning to "explore new opportunities", a statement from ESI, which publishes the Evening Standard, said.
ESI is searching for a replacement. In the interim, the senior commercial team will report to chief executive Mike Soutar, who joined the business in October.
O’Donnell joined the Evening Standard as deputy commercial director in 2008 and became group commercial director in 2010. He has been key to the transformation of the brand to a free distribution model and then into digital.
He said: "I have been privileged to work with some incredibly talented people during my time at ESI Media and together we achieved some extraordinary things. Driven by a fantastic culture, I am incredibly proud of the strong commercial business we built and I wish them every success for the future."
During O’Donnell’s tenure, ESI was awarded Cross-Media Sales Team of the Year at the 2016 Campaign Media Awards and was shortlisted for Sales Team of the Year at the 2017 Media Week Awards.
Soutar added: "I've enjoyed working with Jon over the last couple of months since I joined the business. He is a talented and popular executive, and he has contributed so much to the success of ESI over the last decade. On behalf of everyone here, I'd like to thank him for his hard work and wish him the very best of luck with his future plans."