Mike Ashley will step down from his role as boss of Sports Direct.
The Newcastle United owner founded the retail store in 1982 and owns a major share in its parent company, Frasers.
Ashley will relinquish his role as chief executive and hand over the reins to his daughter's fiance, Michael Murray, is currently "head of elevation" at Frasers.
The company oversees brands such as Sports Direct, House of Fraser, Flannels and Jack Wills.
Ashley will remain on the company's board as executive director.
The Frasers board told investors that a pay and bonus deal is being drawn up on the basis that Mr Murray, who is engaged to Ashley's daughter Anna, will become chief executive.
The company said in an announcement to the stock exchange this morning: "The group's elevation strategy is transforming the business and receiving positive feedback from consumers and our brand partners, especially on projects such as the new Oxford Street Sports Direct which opened in June 2021."
"The board consider it appropriate that Michael leads us forward on this increasingly successful elevation journey."
Chris Wootton, Frasers Group's finance chief claimed the change had been in the pipeline for some time with the company needing a new approach.
"Without insulting him, by Mike's own admission he is a bit of a dinosaur. Michael is young, fresh and youthful and knows what the customer wants. Mike is very good at selling socks," he told The Times.
Ashley founded Sports Direct in the Berkshire town of Maidenhead back in 1982 and has continued to expand his retail empire to be worth around £3bn and cover include 1,000 stores.
The retail tycoon has faced criticism for not investing in Newcastle despite amassing a huge fortune.
Since buying the club in 2007 Ashley has twice seen them relegated and last term they were again facing a battle to avoid the drop.
Player recruitment has followed a strict strategy which placed an onus on profit and only buying players under a certain age.
Current Magpies boss Steve Bruce, who has not always enjoyed the affection of fans, is set for a new deal.
Newcastle are yet to make any major signings in the summer transfer window thus far which will increase frustration among fans.
The loan arrival of Joe Willock was crucial in their late season surge but the midfielder is unlikely to return from Arsenal leaving Bruce to eye other targets.