Gandolfini died in Rome, Italy of a possible heart attack, according to HBO.
"We're all in shock and feeling immeasurable sadness at the loss of a beloved member of our family. He was special man, a great talent, but more importantly a gentle and loving person who treated everyone no matter their title or position with equal respect," HBO said in a statement. "He touched so many of us over the years with his humor, his warmth and his humility. Our hearts go out to his wife and children during this terrible time. He will be deeply missed by all of us."
His managers, Mark Armstrong and Nancy Sanders, also issued a statement: "It is with immense sorrow that we report our client James Gandolfini passed away today while on holiday in Rome, Italy. Our hearts are shattered and we will miss him deeply. He and his family were part of our family for many years and we are all grieving."
A New Jersey native, Gandolfini graduated from Rutgers University and was a bartender and a club bouncer before he started taking acting classes.
One of Gandolfini's earliest roles was in a 1992 Broadway production of On the Waterfront. He made a name for himself the following year, playing a mob enforcer in the 1993 thriller True Romance. The next year, he played a violent Russian mobster in the action film Terminal Velocity, and in 1996, he played a mob enforcer in The Juror.
However, it was Gandolfini's turn as mob boss and family man Tony Soprano in the critically acclaimed HBO series The Sopranos that earned Gandolfini worldwide fame. He won three Emmys, three Screen Actors Guild Awards and a Golden Globe for his performance and eventually earned $1 million an episode for the series. The Sopranos was not only a huge success for HBO, but is also considered one of the best TV shows of all time. The Sopranos was recently named the best TV show of all time by the Writers Guild of America.
After his success with The Sopranos, Gandolfini continued to dabble in films including The Mexican, The Taking of Pelham 123, In the Loop, Zero Dark Thirty and Not Fade Away, his reunion with Sopranos creator David Chase.
After The Sopranos came to an end in 2007, Gandolfini collaborated with HBO on several other projects. He produced two documentaries: Alive Day Memories: Home from Iraq and Wartorn: 1861—2010, as well as the TV movie Hemingway & Gellhorn. He also starred in the TV movie Cinema Verite and was set to produce and star in a new series for the network, Criminal Justice.
He also returned to the theater post-Sopranos, most notably co-starring in the award-winning play God of Carnage.
Gandolfini is survived by his wife, Deborah, and his son, Michael and daughter, Liliana.