The 59-year-old, who oversaw failed merger with Asda, to be replaced by Simon Roberts

Sainsbury’s has announced that its chief executive, Mike Coupe, will retire in May after six years in charge of the UK’s second largest supermarket chain.

The 59-year-old will be succeeded by the grocer’s retail and operations director, Simon Roberts.

Coupe has faced questions about his future since April, when the competition regulator blocked Sainsbury’s attempt to take over its Walmart-owned rival Asda for £7.3bn. Coupe was the architect of that deal and Sainsbury’s share price has fallen 22% over the past year.

Sainsbury's to cut hundreds of management jobs Read more

Roberts, a former managing director of the health and beauty retailer Boots, joined Sainsbury’s in 2017, with oversight of the logistics systems used by the company’s 1,400 stores as well as online operations.

Coupe was appointed as head of the supermarket in 2014. He oversaw the £1.4bn acquisition of the catalogue retailer Argos in 2016 but Sainsbury’s share price has fallen by more than 30% from the date he took over.

Coupe will also be remembered for his “hot mic” rendition of the Broadway musical number We’re in the Money on the day he announced the Asda deal. The merger was ultimately vetoed by regulators over fears that a supermarket with a combined market share of more than 31% would reduce choice for customers.

The retail analyst Nick Bubb said Coupe had “at last paid the price for the failure of last year’s Asda deal”. Clive Black, an analyst at Shore Capital, an investment bank, praised Coupe’s tenure but said he had “materially overextended the business’s capabilities in the eyes of the regulator with the proposed Asda merger”.

Coupe has agreed to waive his bonus and share awards for the 2020-21 financial year as he hands over to Roberts.

He described his time as Sainsbury’s boss as “the most challenging and competitive of my 35-year career in retail”.

He said: “This has been a very difficult decision for me personally. There is never a good time to move on but as we and the industry continue to evolve, I believe now is the right time for me to hand over to my successor.”

Sainsbury’s profit is forecast to fall in its 2019-20 financial year. On Tuesday the supermarket said it expected to cut hundreds of jobs in management roles as part of a plan to save £500m in costs by 2024. The chain, which employs 178,000 people, will also have to contend with an expected increase in online grocery orders. Online orders account for almost a fifth of Sainsbury’s total sales.

Sainsbury’s shares fell by 2.2% to 208p in early trading on Wednesday.

The appointment of the 48-year-old Roberts to one of the most high-profile jobs in British retail raises the question of whether he will further adapt Sainsbury’s strategy that was set out in September and was designed to show the group could prosper on its own. The reorganisation included the closure of up to 15 supermarkets and 40 convenience stores, as well as putting 80 new Argos outlets inside Sainsbury’s sites.

Roberts’ task will be to grow earnings in the face of softening consumer demand and the relentless march of the German-owned discounters Aldi and Lidl, who continue to aggressively open new space and win market share.

Roberts joined Sainsbury’s in July 2017 after 13 years at Boots, including serving as president of Boots UK. His former Boots colleague Ken Murphy is due to take over Sainsbury’s major rival Tesco later this year.

Sign up to the daily Business Today email or follow Guardian Business on Twitter at @BusinessDesk

Before Boots, Roberts spent 15 years at Marks & Spencer after initially joining as a 16-year-old. His base salary on appointment will be £875,000.

“Simon has been extremely effective during his three years at Sainsbury’s, leading our store teams through great change in that time,” said Martin Scicluna, Sainsbury’s chairman.

“Simon is a dedicated, determined and enthusiastic champion of the customer and of our colleagues and has overseen sustained improvements in our competitiveness during his time so far.”