While not yet disclosing the locations of the stores to close, Lewis said that a significant proportion would be its Express convenience shops.
The chief executive would not give any details on the scale of the jobs to be lost or whether they were likely to be in the thousands. Head office jobs will also see cuts as overheads are slashed by 30%.
The company will also axe plans to open 49 new stores.
Additionally, the retailer is scrapping its staff pension scheme, which has debts totaling 3.4 billion pounds ($5.14 billion US). It costs the company 500 million pounds ($756 million US) a year and has 350,000 members, of whom 200,000 are current employees.
It will also close its near 40-year-old headquarters at Cheshunt in 2016 and make Welwyn Garden City the site of its new HQ.
The company has now confirmed that two of its businesses — Tesco Broadband and the online entertainment service Blinkbox, will be sold to TalkTalk Group.
No final dividend will be paid for the current financial year. Additionally, from June 1, 2015, the retailer Halfords' boss Matt Davies will step in as Tesco's UK and Ireland CEO.
The measures are set to improve the struggling business; its year-on-year sales for the 19 weeks to January were down by 2.9%. In the third quarter of 2014, its sales had dropped by 5.4% year-on-year.
Last year, the company was embroiled in an accounting scandal, and saw the departure of some senior executives.
Tesco, founded in London in 1919, is a multinational grocery and retailer based in Cheshunt, Hertfordshire. The company currently operates some 6,500 stores worldwide.
