When producer Don Gilmore first met Linkin Park in 1999, he had no idea how big the band would become. But he did know they had something special with singer Chester Bennington.

"I'd never really heard somebody sing that incredibly just in a little crappy rehearsal room," Gilmore tells Billboard of their first meeting.

Together, Gilmore and the band would record Linkin Park's debut album, Hybrid Theory, and its follow-up, 2003's Meteora -- two albums that have sold a respective 10.5 million and 6.2 million copies in the U.S., respectively, according to Nielsen Music -- topping sales charts and defining the band's sound in the process. During the often-difficult recording sessions, Gilmore says he constantly pushed the band members to write better parts or deliver better performances -- and without fail, they proved up to the task.

As a producer, Gilmore's other credits include albums by Avril Lavigne, Sugar Ray, Train, Dashboard Confessional, Good Charlotte, Korn and more, and he also engineered seminal albums by Pearl Jam and the PJ-Soundgarden supergroup Temple of the Dog. Throughout his career, Gilmore says Bennington's performance in the studio was one of maybe just five times he's gotten chills from something so good, calling him one of this generation's greatest rock singers.

Following Bennington's death Thursday, Billboard spoke to Gilmore about working with Linkin Park so early in their career, the band dynamic, and that time Bennington nearly destroyed his recording studio.

When and how did you first meet the band?

I produced their first two records. This is going back a long time; we're talking like 1999 or something. The demos were brought to me through my manager and I thought it was good. I didn't necessarily think it was amazing, but I liked that they were trying to do something unique. So I met with them -- they were looking at some other producers -- and I went to a rehearsal, and Chester started singing and I was just like, "Oh my god, this is really special." I'd never really heard somebody sing that incredibly just in a little crappy rehearsal room. He wasn't really singing like that on the demos, and I just felt like, if he can sing like this in the studio, then we might have a chance of doing something.

What was your first impression of the band, and specifically of Chester?

He was just a nice young kid. The whole band were nice guys. In my opinion, in that first rehearsal he overshadowed the whole band; he was such a huge force vocally that it got me really excited about the project and it made me want to work with them really bad. So then I really lobbied hard to try to get the record. They did choose me, and we went into the studio and we worked really hard. We made that record in like six weeks -- a pretty short amount of time -- and looking back on it, when you listen to that record it's like, wow, we did a pretty good job. It all kind of came together.

There's been a lot of talk about how the record was made, but I found something in the band that... as a producer, you're always looking for special things that kind of stick out and are extraordinary, because sometimes it can take just an ordinary record -- maybe it has good songs and it sounds good and maybe you're fine -- but when you can marry all that with something like Chester's singing, then it's just unstoppable.

At the time, Chester had been the last member to join the band, having been recruited coming out of the Phoenix music scene. What was the band dynamic at the time?

I think he was finding his way with the rest of the guys. They're all really good guys, so they were all welcoming him, but I think that he was sorting through a few things personally -- getting his then-wife out here to visit; I don't even know where he was living, he might have just been crashing on somebody's couch -- but him kind of integrating into the whole thing. I don't think he was completely dialed in to the band [yet]. But he got along with them just fine. He was a good guy, so it worked out well for them.

Did anything about them stick out as distinct or memorable back then?

Honestly, they were pretty green. They've become this amazing band over time, just like every band that's been around as long as they have -- you go to see them live and they're amazing. But back then they were young kids. Mike Shinoda really is a talented guy; he rose to the occasion as a lyricist and as a programmer and as a songwriter, he was very good. And Chester and him and I working together on that first record, it was just so good. Chester was really involved in all the writing on the first record. Maybe a little less so on the second record, but nonetheless he was very, very involved.

There was all this talk about how it was a hard record to make, but as a producer, when I ask artists to do certain things -- like, "I think you can rewrite that and make it better," or "I think you can sing that better" -- and sometimes they don't come back with it written better or they don't go out and sing it better, then I'll try again a few more times, but sometimes you just never get there and you go with whatever. But with these guys, when I'd ask for these things and I'd push them to do better, they would. They would maybe get frustrated and angry, but the results were insane.

When we finally played it for the record company... The record company had kind of just signed this band that they thought was a normal rap-rock group that would do okay. And when they first came in and listened to it, their jaws were on the floor, they couldn't believe it. They were bringing everybody from the record company over to listen to the album in the studio and there was so much excitement. And then it became a huge priority instantly for the label.

What were the recording sessions for Hybrid Theory like?

Back then, I would build kind of a little cube for the singers, to take the standing waves out of the room when the microphone was very dry and dead-sounding, almost like a little fort or enclosure for him to be inside. And they were working on "One Step Closer" -- the song was written in the studio -- they were working on the riff and they were writing the lyrics and those were flowing out nicely. And then it was time to sing. And Chester sings the whole song, but then we have the bridge, the breakdown in the middle of the song -- the "Shut up when I'm talking to you" part -- and there was a lot of going back and forth, and they couldn't really find what they wanted to say. There were different lyrics written, we were saying maybe it could be a musical section, and then Mike and Chester came in with this and Chester went out and sang it and it was just overpowering. He knocked the walls down in the little fort. When he sang it, he just literally destroyed the whole thing and almost broke the microphone. He was just out of his mind. And the rest is history.

There are lines like that where if you don't perform it all-in, they're not going to work, right?

Yeah. I mean, for a record producer he was just a dream come true. He could go to that point that was, like, beyond -- it's just crazy how hard he could go with such precision. And even when he sings softly, the precision [was there]. So yeah, he was a super special guy.

What was so special about Chester's voice? How was it distinct from others you've worked with?

Not to take anything away from the guys or anything, but they might have been looking for a different kind of singer. Then they found this guy from Arizona, and he could go into the rock world in such a way that maybe wasn't exactly their cup of tea. I think that they wanted to be more like Incubus or something like that, but once Chester got his voice down on tape it was so undeniable, I was just like, "You guys, people are going to freak out over this. This guy, there's nothing like this." It was pretty obvious. I don't think I had to sell them very hard on it, and Chester loved to sing like that.

What did you think about Hybrid Theory when it was finished?

For me, the way my whole career and my little system works is I just make sure that I tick every box. I need to know that the songs are right from a lyrical point of view, that they're honest, that they're not cheesy, that it's recorded properly, it sounds good, it fits into a place where it can be marketed. But with this thing, it had all that stuff, but it had other things too. Honestly, I thought it was really good, I thought it was great work, but I didn't know it was going to be that big. I worked on Pearl Jam's [debut album] Ten, and I didn't know that that was going to be that big. I just kind of try to do my best work, and when you work super hard long hours and you've got to keep your head on a swivel, you just kind of work, work, work, work, work and then drop at the finish line.

I don't even know how many millions of records it sold, but I would have been so happy for it to just sell 1 million records and have another platinum record on my wall. But it turned out to be many more than that.

After all that success, had things changed by the time you guys started working on the second album?

They were rock stars at that point -- how are they going to follow that up? And really, I'm not sure they wanted to use me on their second record; I'm not really sure why, but Chester and Tom Whalley, who was at the time CEO of Warner Bros., they really wanted me to do it. And I was very thankful to Chester for that. And the guys, they went along with it. They might have been talking to some other people, but that's their thing. When we went in and did Meteora, it was such a fun, easy record to make, because Tom Whalley was super supportive; he didn't have one negative comment to make the whole time, he was just a positive energy around the band, and Chester and Mike just continued to be amazing.

Was anything different about that project or recording process?

It was basically the same, I would say, but I think the understanding and the sphere of this guy that's an outsider -- you know, "I'm outside the group" -- there was a trust element that was there on Meteora that maybe wasn't quite there [before]; at times it was a bit contentious during the Hybrid Theory sessions. But on the Meteora sessions, not so much, because if I asked them to do stuff that was outside of their comfort zone, they were fine with going there and trying to find those special moments. And they did it again on that one too.

What memory now sticks out to you the most about what Chester was like?

The thing that is so disturbing about this -- and granted, I haven't been in touch with him in a long time -- he was a guy who maybe had a few problems, but he would kind of talk about them. "Oh, this and that. My wife is doing this. Oh, I've got to go do this." Just normal stuff that we all do. And he liked to laugh, he had an amazing sense of humor. On Meteora, he set up this little ProTools rig out in the lounge and he would write these little funny punk rock songs and record them and bring them in and play them for us. But I mean, he just was a funny guy, it was awesome. It's just, boy, such a sad, sad thing.

What do you see as his legacy?

His body of work. I think that they've touched so many people around the globe, they've maintained this kind of... They didn't go all the way there and sell out. They kept their brand really simple and honest, and I think that it's really cool that all these different cultures, all these people around the world, know who Linkin Park is and they can sing a lot of their songs, even though they don't speak English. I think that's such a cool thing.

I've maybe had four or five times in the studio that I got goose bumps, literally like shivers, and one of them was with Chester, for sure. And oddly enough, one of them is Chris Cornell, when I recorded Chris on the Temple of the Dog record.