Songfacts®:

• This song features Rivers Cuomo. The collaboration came about after the Weezer frontman started communication with the New York trio of brothers via social media. He recalled to Billboard:
  
  "I kept hearing 'Weak' on Spotify's Today's Top Hits. It reminded me of Weezer a little bit; if I were in my mid-20s right now, I'd be trying to do something like that. So I followed them on Twitter. They asked if I wanted to help them finish a song for their record, and sent me a rough track saying it needed a bridge."
  
  AJR's Ryan Met added: "Weezer redefined what a rock star was. [Rivers] took 'Sober' and elevated it. When we were making it, we didn't think this was going to be pop, rock or alternative. We wanted to make something we would want to listen to, forget about the restrictions."
• AJR explained the song's meaning in a Genius attribution: "'Sober Up' is about that first crush elementary school, before you knew what love was, and reminiscing: questioning if you can ever get back to that simplicity in an emotion."
• AJR's Jack Met thinks the appeal of the song comes from its universal theme of longing for things to be simple again, like they were in childhood. "The idea came when Ryan and I were in college," he told Billboard. "We did our first couple of semesters at Columbia, we were experiencing the whole college vibe, going to parties and doing that sort of thing."
  
  "And then there was a time where we just started getting depressed a little bit," Jack Met continued. "We started getting sad because we felt a little bit too grown up, because one of the things we kind of pride ourselves on is staying young and having that little-kid experience. And we thought that we felt a little bit too adult and we wanted to go back to that feeling we used to have in elementary and middle school, where we kind of just liked a girl and that's all there was to it. 'I just like this person without having all of that other baggage that comes along with it.' We thought we'd write a song around that, around me calling my second-grade crush and saying, 'I kind of want to go back to the feeling we used to have.' And I think that's honestly something everyone can just relate to. I don't think I've ever met a person that doesn't feel the need to go back to being young."
• When "Sober Up" topped the Billboard Alternative Songs chart, AJR became the first band consisting solely of family members to reach #1 on that particular tally since Kings of Leon (three brothers and a cousin) did so with "Waste A Moment " beginning December 3, 2016.