Tesco is at the back end of a recovery plan under Lewis that was instigated after a 2014 accounting scandal capped a dramatic downturn in its fortunes.
Tesco, Britain's biggest retailer, said on Wednesday its chief executive Dave Lewis will step down next summer and be succeeded by Ken Murphy, an executive at Walgreens Boots Alliance.
Celebrating its 100th anniversary, Tesco, which has a 27.4% share of Britain's grocery market, is at the back end of a recovery plan under Lewis that was instigated after a 2014 accounting scandal capped a dramatic downturn in its fortunes.
The group has met the majority of its turnaround goals, including a key margin target of earning between 3.5 pence and 4 pence of operating profit for every pound customers spend.
Lewis' planned exit after six years at the group came as Tesco reported a better-than-expected first-half operating profit before one of the items of 1.406 billion pounds, a rise of 25.4%.
"With the turnaround complete and as we begin to implement the next steps of our sustainable growth strategy, now is the right time to plan a smooth and orderly succession," said Lewis.
"As such, I will step down as group CEO next summer and pass the baton to Ken Murphy."
Murphy was a joint chief operating officer at Boots UK & Ireland before rising to executive vice president, chief commercial officer and president global brands at Walgreens Boots Alliance.