Profits at Mike Ashley's Sports Direct plunged 33.5% to £145.3 million in the first half of the year following the collapse in sterling.
The group, which has endured a long list of controversies over the past months, compounded its PR problems by failing to hedge against the fall in the value of the pound in the immediate aftermath of the EU referendum.
Sports Direct warned that it expects "strategic challenges and currency headwinds" to continue to adversely affect its financial performance in the medium term.
Mr Ashley said: "The last six months have been tough for our people and performance. Our UK Sports Retail business continues to be the engine of Sports Direct, but our results have been affected by the significant deterioration in exchange rates, and our assessment of our risk relating to our stock levels and European stores performance."
The company said revenue rose 4.2% to £1.6 billion, but warned of a challenging environment which the firm expects to continue into the "foreseeable future". On a pre-tax basis, profits slumped 57% to £71.6 million.
The results come after a string of controversies for the firm which has seen billionaire Mr Ashley hauled before MPs to be grilled over working conditions, the company host a tumultuous "open day" at its headquarters, and its chief executive Dave Forsey, quit - only to be replaced by Mr Ashley.,
Mr Ashley sought to address the shambolic year through the trading statement, claiming again that he would like Sports Direct to become the "Selfridges of sports retail".
"What matters most to me is how tough the last year has been for the people who work at Sports Direct. Our people have once again found themselves in the spotlight through no fault of their own, yet they remain hard-working and loyal.
"It is for this reason that my immediate priority will be to protect the people at Sports Direct," he said.
Despite the Financial Reporting Council announcing an investigation into Sports Direct over the retailer's relationship with a firm owned by the tycoon's brother, the company said it has entered into an agreement with Double Take Limited, in which Matilda Ashley, Mike Ashley's daughter, is a director.
Double Take will licence Sports Direct exclusive rights to the cosmetic brand Sport.