His departure is expected to allow new leadership to conduct the restructure and turnaround of the business.
Debenhams entered a pre-pack administration last week (9 April) and will continue trading while its lenders look to sell the business. The department store acquired £200m funding, a new investor group and a business plan which it said was expected to “deliver a recovery in profitability and deleverage its balance sheet”.
Non-executive chairman Terry Duddy will step in as the interim executive chairman.
Bucher said: “Now that our new financing facilities are in place, it is time to move on, knowing the company is in good hands with a plan that will deliver a sustainable future.
“I would like to wholeheartedly thank all of my colleagues for their efforts and dedication during such a turbulent time, as well as our suppliers, partners and of course customers for their continued support.”
Duddy added: “Debenhams now has a clear path towards a viable and sustainable future. We have Sergio and his team to thank for that. With a positive, professional approach, he has acted at all times in the company’s best interests, and we wish him all the best for the future.”