Grey was battling cancer at the time of his death, his family said in a statement to CNN.
Grey exited Paramount in February after running the studio over a 12-year tenure that saw him oversee massive hits with films in the Star Trek and Transformers franchises.
Grey was hired by former Viacom CEO Tom Freston to run Paramount Pictures in 2005, replacing Sherry Lansing.
"All of us at Paramount are deeply saddened by the news of Brad Grey's passing", Gianopulos said.
Before taking on the Paramount job, Grey formed the Plan B production company with Brad Pitt and Jennifer Aniston, which began with a first-look deal at Warner Bros., where it producedTim Burton's Charlie and the Chocolate Factory and Martin Scorsese's Oscar best picture victor The Departed.More news: Key state election kicks off in Germany's North Rhine-Westphalia
Prior to leading Paramount, Grey built his former company, Brillstein-Grey Entertainment, and also was a co-founder of Plan B Entertainment alongside Brad Pitt and Jennifer Aniston.
His death shocked Hollywood, with few people in the industry apparently aware that he had been ill with cancer. "As a producer and industry leader, Brad brought great storytelling to audiences around the world, and his contributions to the creative community will be enjoyed for years to come". Grey led the acquisition of DreamWorks SKG, the studio created by Steven Spielberg, David Geffen and Jeffrey Katzenberg.
Grey was born December 29, 1957, in New York City. And as he tracked new comics, he discovered his first client, the comedian Bob Saget.
Grey is survived by his wife, Cassandra and their son, Jules and his three adult children, Sam, Max and Emily, his mother Barbara Schumsky and siblings Michael and Robin.
The family asks that, in lieu of flowers, donations be made to the Lawrence J. Ellison Institute for Transformative Medicine of USC.