The sportswear retailer said that Everlast's platform in the US, where Sports Direct has a limited presence, will help it launch other group brands into the American market.
The acquisition remains subject to the approval of the Everlast shareholders and is expected to be completed during the second half of the year. Credit Suisse is acting as financial adviser.
Sports Direct chief executive Dave Forsey said: 'The Sports Direct board is confident that this acquisition will benefit our wholesale, licensing and retail businesses, while providing us with a significant stepping stone into the important US market.'
In fiscal year 2006, Everlast generated sales of US$39.6 million (£19.8 million) and EBITDA of US$9.3 million (£4.6 million).