The firm's spokesman Ron Berkowitz confirmed the news, and Durant later tweeted out a picture on Monday afternoon of he and Jay-Z signing the papers. ESPN.com initially reported on June 8 that the partnership was expected.
"Grateful for this opportunity with Roc Nation Sports," Durant said, in the text above the tweeted picture. "It's go time."
"He has a 90.5 free throw shooting rate, the youngest player in NBA history to join the 50-40-90 club," Jay-Z was quoted as saying, above the picture. "A giving individual and a legend in the making. What more can I say?"
The move was expected for two weeks, since Durant told his former agent Rob Pelinka that he was jumping ship and wanted to try partnering with the power of Jay-Z.
The partnership will immediately test Jay-Z's ability to score out-of-the-box marketing deals.
After all, Durant is one of the most bankable athletes in all of sports, having endorsement deals with Nike, Sprint, Gatorade, Skullcandy headphones, BBVA Compass, 2K Sports and Panini America.
Although Durant will be a full client of the firm, he doesn't need a contract agent because he signed an $85 million extension with the Thunder in 2010 that will take him through the 2015-16 season.
Perhaps that's the reason why Durant can be signed, even though a source told ESPN.com last week that Jay-Z had not sold his small ownership share (1 percent) of the Brooklyn Nets. An owner of a team cannot have any affiliation with a sports agency that represents players in contract negotiations. Jay-Z can, however, do marketing deals now even if his share of his Nets holdings hasn't been sold.
Aside from Durant, Jay-Z's sports clients currently include New York Yankees second baseman Robinson Cano, New York Jets quarterback Geno Smith and former Notre Dame guard Skylar Diggins, who is playing in the WNBA for the Tulsa Shock. It's also believed that Jay-Z will be representing New York Giants wide receiver Victor Cruz in some capacity in the near future.
Last week, the NBA's and Major League Baseball's players' unions confirmed that Jay-Z himself was licensed to represent players in contract negotiations. Jay-Z doesn't have a license to negotiate contracts for NFL players, which has been a concern for the NFLPA.
The union is currently investigating whether Jay-Z violated the Runner Rule, which states that a person who doesn't have a license to represent players cannot recruit players to join an agency.
Smith's Roc Nation agent is newly hired Kim Miale, who has never represented a big-time client.