It said strong demand at its core sports division drove a doubling of profit before tax to just shy of £20m, with revenues climbing 27% to £721.5m in the 26 weeks to August 2.
First-half sales at stores open over a year in the sports division, which sells trainers and other sportswear, rose 13% on the same period last year.
Like-for-like sales at its Blacks and Millets outdoor retail chains, bought from administrators for £20m more than two years ago, increased 12%.
JD Sports, which has the bulk of its 850 stores in the UK, said it now expected its full-year profit performance to be at the upper end of expectations - though its guidance hinged on trading during the crucial Christmas period.
The firm announced in May that its chief executive, Barry Bown, had stepped down and would not be replaced.
The group's growth strategy has long been led by executive chairman Peter Cowgill, who also takes a key role in the day-to-day running of the company.
He said: "The group has delivered record results for the first half, with encouraging progress in the principal areas of the business, notably our UK and European sports fascias.
"Our sports operations continue to provide the engine for profit growth and cash generation in the group and will therefore continue to be the primary focus of investment.
"The board recognises the demanding comparatives of the second half of the last financial year, particularly in the core UK and Ireland sports fascias, where like-for-like sales increased by 11.2%, as well as our significant dependence on Christmas trading but following the robust performance of the business in the first half believes that the group is well positioned to deliver results towards the upper end of current market expectations".