The Chatteris store enjoyed a successful first morning, right, with hundreds pouring through the doors at 10am to be greeted with champagne, bacon sandwiches and cupcakes.
"Jack Cohen championed value for customers and changed the face of British shopping,"Dave Lewis, Tesco Group chief executive, said about the new project". A second outlet opened yesterday in Immingham, Lincolnshire.
Jack Cohen founded Tesco in 1919.
Tesco said that eight out of 10 Jack's food and drink products will be "grown, reared or made" in Britain and stores will stock an own-brand range, also branded Jack's.
Shares in Tesco were up 0.5 percent at 236.3 pence in late trading on London's benchmark FTSE 100 index, which was half-a-percent higher overall.
To compete with them, Jack's would have to expand rapidly while undercutting Aldi and Lidl's prices at a time when the two incumbent discounters are bound to review their own costs in a bid to show the new kid on the block who rules this roost.
However its dominance is also threatened by another big deal as "Big Four" rivals Sainsbury's and Asda plan a £15billion merger that would make a combined company the biggest supermarket chain by share.
Sir Jack, who was born Jacob Edward Kohen to Polish parents in 1898, was a Whitechapel grocer who served in the British Army in Egypt and Palestine during the First World War before returning home to establish the business in Hackney.
"It's fitting that today, we mark the beginning of Tesco's celebration of 100 Years of Great Value by launching a new brand bearing his name: Jack's".
With the new chain, Tesco has to walk a fine line, challenging the discounters while avoiding cannibalisation of its main store brand with lower prices.
The concept will roll out over the next six months, with around 10-15 Jack's locations slated to be opened around the United Kingdom.
In contrast, Aldi and Lidl had grown their respective market shares to 7.6% and 5.5% respectively. But, it seems, another way to beat the discounters is to play them at their own game.
The flag-waving also lets Tesco contrast its United Kingdom roots with the German ownership of Lidl and Aldi, at a time when Brexit has heightened some Britons' awareness of nationality. "However, it is undeniably an innovative move that's sure to apply further pressure to the other mainstream retailers".