The two stars teamed up onstage in God of Carnage and Daniels, as part of his ongoing tribute to the late The Sopranos star, admits the only reason the acclaimed play hit New York's theatre district in the first place was because of Gandolfini's involvement - and the kind-hearted actor made sure all the cast reaped the benefits.
Daniels tells Msnbc, "I remember when we extended, Jim's first thing was, 'Everybody gets paid the same or I don't do it'. He did things like that constantly."
Gandolfini and his three castmates were all Tony nominated for their roles and Marcia Gay Harden, who portrayed the actor's partner onstage, picked up a Best Actress honour.
Daniels admits it was an honour to work alongside The Sopranos star and watch on as he realised what a good actor he was.
The Newsroom star adds, "It was so brave of him to come to Broadway; that's the proving ground - a lot of film actors can't do it. It's eight times a week. It's tough to make it look like it's happening for the first time.
"I think there is part of Jim that looked at The Sopranos as this 'I don't wanna be a one-hit wonder' and 'I'm a big star, but am I good actor?' and he came to Broadway with God of Carnage to prove to himself that he was a good actor and it was a joy... to watch him feel good about what he did as actor."
Gandolfini suffered a heart attack and died while holidaying with his son in Italy on Wednesday (19Jun13).