With the characters and a script finally locked in, Ellin, Levinson and Wahlberg set about finding actors to bring the entourage to life.

Ellin: It was probably like a six-month process to cast these guys. I wanted guys that I grew up with and it was really hard to find that. We had amazing actors come in for these parts that have had enormously successful careers, but they just weren't The Guy. You know?

The second Adrian [Grenier] got in front of the camera...It felt like he was this movie star, he had this "Why don't I know who this guy is?" quality. It started out looking for someone so much closer to Mark than Adrian was [but] once we got Adrian, it was so clearly the right way to do it.

Jerry Ferrara: At the time I had just signed with Steve Levinson. Not that I had an inside track, but I knew about the project. I had a meeting with Doug, where we kind of talked about what the world of the show was going to be like. At one point the show was a little bit darker and edgier, and then Doug had gotten some notes from HBO to make it lighter and more fun, and I came in on that version.

Kevin Dillon: I remember when I first went in, I told [my agent] I don't know what I can do with this material because it's a four-character piece and my character [at the time] had one small line here, one small there. She's like, "You've got to go in, it's HBO." And I said, "Okay, well can I do some of the other guys lines?"

Ellin: There's no one on the planet Earth that could have been better than Kevin Dillon.

Larry Charles: Kevin Dillon playing Drama could not have been more brilliant casting. He brought that character to life, it was very distinctive. It was really fun to write for him.

Dillon: I got all the laughs that I needed and felt good about it.

Ellin: From the second he walked into the room, I looked at Steve and I said, "This guy's going to win an Emmy."

Ferrara: I don't even know if they still do it like this anymore, but I got invited to the network test, which is the final stage, the final boss to beat. What they pretty much do is they bring two or three choices for each role, and they sit everyone in the lobby. So you're looking around like, "Wow, there's the Vinces, there's the Es, there's the Turtles." You see everybody who's reading for which role—there was only one Johnny Drama. Kevin Dillon was the only person. It's almost like they were trying to lock the network in. "We're not even going to give you another option, that's how much we love Kevin Dillon as Johnny Drama."

Dillon: It's easy when you get really good dialogue that you knock it out of the park.

Ferrara: We were in that network lobby, waiting, everyone's all nervous, Dillon stands up and is like, "Who else here is reading for Johnny Drama?" Connolly was like, "Nobody, it's just you. We're pretty sure you fucking got it." And Dillon goes, "Oh, all right. I'm going to go run out and hit the head and smoke a cigarette." I'm like, "Oh man, this guy is the fucking best."

When you go for your reading, you're in a black box. It's basically a theater but you can't really make out faces. So I wasn't even sure if Mark was there or not, and sure enough he was. He comes out of the room, pulls me over, and he whispers, "I just wanted to come out here and tell you, you're kind of blowing it right now. It's not that you were bad, you just weren't doing all the stuff you were doing, that got you [this far]. You were like this energetic, funny, New York kid—[now] you’re playing it a little safe, and I think you're blowing it. Just be you. I don't give a fuck about what the script says. Just give us the essence you were giving us, and you'll be all right." So that almost was like a punch in the face. It woke me up in a way.

Ellin: When we put Jerry Ferrara and Kevin Dillon in a room...I don't want to give the wrong ages, but Jerry was 23 or something and Kevin was 36 to 38—and we were pretending they go to high school together. I used to have fucking nightmares about this. I told Jerry not to shave for weeks before we tested him at HBO.

Ferrara: I don't even think I really had any facial hair yet. We were trying on all these bigger jerseys that I had, and just doing anything to make me look older, because I think Doug, Lev and everybody were worried that they were just going to go with someone who looked older to match up with everyone else. Because Kevin Dillon was a shoo-in.

Dillon: I remember the first time I met Jerry it was like a second audition, this callback. And he was sitting there [with] a pack of cigarettes. I [mooched] one and we got to talking about which part of New York we’re from. So I got to know Jerry a little bit and I ran into Kevin Connolly at one of [the screen tests]. We just all hit it off right away. It's that that New York guy kind of attitude and we just bonded right away.

Ferrara: I obviously knew Kevin Dillon, his work. I loved Platoon, The Doors, The Blob. When we did our mix-and-match, the first moment that guy opened his mouth, was like, "Oh my God, this dude's fucking hilarious."