In the three years he’s spent working behind the scenes, the artist Alexander 23 has built an impressive resume. As one of the music industry’s go-to songwriters and producers, he’s collaborated with Olivia Rodrigo, Selena Gomez, and Chelsea Cutler, among others, coining a sound that strikes a chord between sharp lyricism and instrumental melodies.

It all started in Deerfield, Illinois, where Alexander 23, born Alexander Glantz, was raised. He became enamored with music “immediately as I gained consciousness,” he says, which he estimates was in “like, the fifth grade.” Around that time, he played on his elementary school’s basketball team, and he enjoyed listening to albums from rock bands like Kansas and Supertramp from beginning to end during the long drives to games. His father helped cultivate that passion, regularly playing the guitar around the house.

Glantz briefly attended the University of Pennsylvania to study engineering but withdrew after a year to focus on music. At 19, he moved to New York and joined an indie band, teaching himself to play bass, piano, drums, and guitar along the way. The group was short-lived and disbanded in 2017. That’s when he moved to Los Angeles with only the earnest goal of writing for other artists — and notably, without a car. He remembers the solo cross-country move as being a strenuous process. “You cannot walk around L.A., which I learned the hard way early on,” Glantz says. “A few expensive Ubers later, I bought a shitty little car.”

While he entertained the idea of being a soloist, Glantz initially figured that working behind the scenes would allow for more financial stability. Having become well-versed in production software like Ableton, he landed himself production credits on tracks for pop musicians like AJ Mitchell and Sam Setton. About “five or six months” after moving to California, he decided to take a chance and record songs of his own while continuing to team up with other artists.

Since then, he’s released two nine-track EPs, including 2019’s I’m Sorry I Love You and Oh No, Not Again! in 2021. His ability to combine live instrumentation with contemporary electronic elements, as well as his knack for describing behaviors for which people often don’t have the words, has made him one of the industry’s most sought-after collaborators. On Aftershock, his proper full-length debut, he details the process of a harrowing breakup, from the first inklings of doubt to finally closing the chapter, over the course of 11 poignant tracks.

“I like to think of it as a one-year-plus-or-minus radius away from a breakup,” Glantz says. “It’s about the events leading up to it, the breakup, then getting over it; meeting new people, thinking you’re ready to meet new people, and you're not actually ready. You miss her, but you don't miss who you were together. It's definitely a breakup album, which obviously I'm not the first person to do, but I tried to really pull from my specific experience and really get into the nitty gritty and all the nuances that I was feeling.”

Aftershock opens with “Hate Me if It Helps,” which sees Glantz unfazed in the midst of his ex’s bitterness. On it, he allows his former partner to blame him for the dissolution of their relationship, even if her accounts are false. Co-written by Olivia Rodrigo, for whom he co-produced “Good 4 U,” the track features Glantz questioning the truth of what his ex is telling her friends and family before issuing saccharine apologies on the bridge. “I’m sorry I stayed up with you every night / For making you laugh when you wanted to cry / I’m sorry I paid for your SSRIs,” he sings.

Many fans have found the line to be playfully tongue-in-cheek, but others have taken to social media to say the lyric further stigmatizes mental health issues. “You know, what's funny about that line is I never meant for it to be a large mental health conversation starter,” Glantz says. “I have plenty of songs about that, as well, but I wanted a line in there that felt like something you would regrettably say in the heat of feeling a certain way about someone or a certain situation.”

On the excruciatingly self-aware “Crash,” Glantz recounts the painful early stages of the split: changing his ex’s name on his phone, dreading Valentine’s Day chocolates (which he says now “taste like charcoal”), and recalling texts he typed up but never sent. While he still has love and respect for his ex, he understands that the two of them are no longer meant to be together. He sings, “I miss you, but I don’t miss us / ‘Cause apart we’re great, but together we suck.”

Glantz admits that he’s learned the hard way that two people, even with the best intentions, can bring out the worst in each other. “The sum of the parts is not always greater,” Glantz notes. “That's something I think people need to learn, especially in more intimate and romantic relationships. It sucks. And I think the fact that it sucks makes you want to fight for it more, which in turn, only makes it worse.”

Glantz’s music is undoubtedly relatable. His ability to put universal feelings, like the train of thoughts and the behavioral patterns that follow heartbreak, into words has set him apart as a thoughtful young musician in an era of quick, hook-heavy TikTok grabs. Take the punchy, percussion-filled track called “Cosplay,” wherein he describes the moment of realizing that he and his ex were never good for each other. He surmises that they were simply imitating the mannerisms and aesthetics of “each other’s exes” from previous relationships.

Perhaps the most powerful track on the collection doesn’t pertain to a breakup at all. On the ballad “The Hardest Part,” driven by gentle piano keys and a melancholy guitar riff, Glantz reflects on the loss of a friend. The song’s chorus — “the hardest part of getting old, is that some people that you don’t love don’t” — evokes a grand feeling of sadness while pointing to the small, intimate moments that make a friendship special. He describes noticing when the “trees turn red” and realizing that he’ll never again see the “three dots” that appear as someone is replying to a text message.

While Glantz paints a vivid picture of his friend, “The Hardest Part” also speaks to the grief and loss every one of us has faced in the wake of the coronavirus pandemic. “This has been the first time where I've had friends start to pass away,” Glantz says. “It's incredibly strange to reconcile. And even when it's not someone who you talk to every day, even if it’s losing someone whom you only speak to a few times a year but have a shared childhood and history with, it’s really strange to deal with. It hits you on birthdays or coming home for Thanksgiving. Learning how to deal with that emotionally has been a journey.”

Over the years, Glantz has opened concerts for several major artists, including Mxmtoon, Omar Apollo, and John Mayer. During a show in Boston, Mayer joined Glantz on stage to perform a cover of Tears for Fears’s “Everybody Wants to Rule the World.” Glantz will tour this fall in support of Aftershock, which he says is the “cherry” on top of making music. As a songwriter and producer, he is always satisfied when he can take another artist’s song to the next level, but as he prepares to perform his own body of work, he admits to feeling a perfectionist’s sense of concern. He knows fans will associate these songs with him forever.

“I remember that, when I'm making music for me, I'm gonna have to live with these songs, both as a representation of me and also my life,” he says. “I'm definitely a bit more particular when making music for myself, which, in turn, makes producing for other people a little bit easier. But making music for others versus myself is just different, more so than easier or harder.”