"It is with huge sorrow that we can confirm that our beloved Nick lost his life at the Bataclan last night. Nick was not just our brother, son and uncle; he was everyone's best friend -- generous, funny and fiercely loyal," Alexander's family said.
"Nick died doing the job he loved and we take great comfort in knowing how much he was cherished by his friends around the world. Thank you for your thoughts and respect for our family at this difficult time. Peace and light."
In addition to serving as merch manager for Eagles of Death Metal, Alexander held a similar role on multiple tours with Sum 41, Panic! at the Disco and the Black Keys.
"I spent a lot of time with Nick, but the thing about the touring merch job, it's one of the more thankless jobs," Black Keys drummer Patrick Carney tells Rolling Stone. "You do it because you just want to travel and you're interested in meeting new people and it's really hard work. It's not the job you take if you're into partying.
"So he was a really organized, super hard worker, really funny. I remember him always very content with being on tour. It was what seems to make him the happiest. After shows, when everyone would go wild or whatever, he would also be really reserved," Carney said. "He was just a sweetheart, that guy."
"Just found out Nick Alexander was one of the people murdered last night in Paris," Fall Out Boy guitarist Joe Trohman tweeted. "Great guy. I'm horrified."
"I remember he looked more like a rock star than anyone else on the tour, in the best possible sense," Carney adds. "He never complained. He was more interested in touring than anybody else that was on tour at any given point."
Carney's Black Keys bandmate Dan Auerbach was in Paris at the time of the attacks with his group the Arcs; Auerbach relayed to Carney that he and his band were OK and that they were locked down in Paris.
"It's unfathomable," Carney says, adding that the Black Keys had played the Bataclan on numerous occasions.
"Every time I go to a football game, you're on high alert because you're around 60,000 people or something. It's in the back of your mind" he says. "But if you're going to see your friends' band play to a thousand usually super-liberal, open-minded people at a theater, it's the last thing you think could happen."
Auerbach tells Rolling Stone of Alexander, "We'd been working with him for years. He was just a familiar face. He was part of our family basically, one of those guys we'd see every time we come over here for these big European experiences we'd been having for 10-plus years.
"He was always there, really nice guy, always with his mod haircut and his big smile ... He was just a really nice guy. Always. Just loved rock and roll. He was just an absolute rock and roll guy. Lived for it," Auerbach says.
In a Facebook post, Alice in Chains also remembered Alexander.
"Our former merch vender Nick Alexander has been confirmed as one of the victims of the senseless violence in Paris yesterday. Nick was a great guy and a true professional. It was an honor and a pleasure to work with him," the band wrote.
"Please keep Nick and his family in your thoughts, along with all of the other victims of yesterday's brutality. Life is short. Be good to each other..."
Friends of Alexander have set up a GoFundMe account for Alexander's memorial fund. By Sunday morning, the page had nearly doubled its $25,000 goal. All proceeds will go to Alexander's family.
Helen Wilson, who was with Alexander in the Bataclan at the time of the terror attack, described the attack to The Telegraph.
"We heard a couple of noises outside and people started running into the club. We didn't know what was going on. Then maybe five, six guys came in with machine guns and shotguns and just started shooting people. It was mayhem. When anyone started running, they would shoot them down. So we got down on the floor," Wilson said.
"Nick was in front of me when we were lying on the ground and somebody moved and they just turned round and started shooting us. His back was to me and I couldn't see what happened and I tried to keep him talking and then I tried to give him mouth-to-mouth resuscitation and [the gunmen] were just sort of in the shadows and they would shoot if anyone said anything. Then he couldn't breathe anymore and I held him in my arms and told him I loved him."
Wilson was wounded in both legs in the attack.
Alexander was among the first victims of the tragedy in Paris to be identified. ISIS has claimed responsibility for the attacks.