Alexander 23 is a pop producer who also makes gentle, lovelorn songs of his own. He emerged in 2019 with a vibe that was part heartbroken slacker and part playfully sparse, software-constructed pop on the single "Dirty AF1s." Maintaining his public anonymity even while he racked up streams for tracks like "IDK You Yet" and the Selena Gomez collaboration "Rare," the singer's identity was later revealed as Illinois native Alexander Glantz. His second EP, Oh No, Not Again!, appeared in 2021. That same year, he gained yet wider attention co-producing Olivia Rodrigo's chart-topping single "Good 4 U" from the Grammy-winning LP Sour. Tour dates with John Mayer and Tate McCrae followed, and his EPs and miscellaneous tracks led up to a studio debut with the 2022 Interscope-released, Dan Nigro-produced album Aftershock.

Raised outside of Chicago in Deerfield, Illinois, Glantz taught himself to play multiple instruments during his high school days and eventually dropped out of college in Pennsylvania to pursue his music career. Several years working as a producer and songwriter in Los Angeles led to the 2019 launch of his own solo career. Without revealing his identity at first (his social media featured the banner "Who is this?"), Alexander 23 issued his debut single on Interscope in March 2019. He followed the release of "Dirty AF1s" with a tour of the U.S. in support of Alec Benjamin and an appearance at that August's Lollapalooza festival. His debut EP, I'm Sorry I Love You, followed that October.

A bevy of songs were released in 2020, including "IDK You Yet," "Loving You Gets Hard," "Brainstorm," and "Rare" with Selena Gomez. A number of these tracks later appeared on his follow-up EP, 2021's Oh No, Not Again! Also that year, he co-produced Olivia Rodrigo's Hot 100 chart-topping single "Good 4 U," off her Grammy-winning album Sour. In April 2022, Glantz returned to his solo work with the jangly breakup anthem "Crash." 2022 also saw Alexander 23 playing live dates supporting John Mayer and Tate McCrae. That June, "Somebody's Nobody" was released as the first single from his full-length studio debut, Aftershock. The album was produced by Dan Nigro and included co-writing credits from Olivia Rodrigo, Amy Allen and Jeremy Zucker. Aftershock was released in July of 2022, and touring plans in support of the record included a headlining tour, support slots for girl in red, and festival appearances that included sets at Lollapalooza and Firefly. He collaborated with Kenny Beats for the song "ill" and released holiday song "Ain't Christmas" with Laufey. The solo single "How to Drive" appeared in 2023. ~ Marcy Donelson, Rovi