The set also starts as the trio's first Billboard 200 top 10.
AJR rules Billboard's Top Rock Albums chart for the first time, with Neotheater bowing atop the May 11-dated list with 32,000 equivalent album units earned in its first week, according to Nielsen Music.
Of that sum, 22,000 were via traditional album sales.
The set is also new at No. 2 on Alternative Albums and No. 8 on the all-genre Billboard 200, where the brother trio tallies its first top 10. The rank surpasses the No. 61 peak of the act's 2017 release The Click.