Leminorella grimontii strain LG-KP-E1-2-T0 was isolated from Zophobas morio larvae. It showed a susceptibility phenotype compatible with the expression of an inducible extended-spectrum β-lactamase. The presence of a chromosomal bla gene encoding for the class A GRI-1 β-lactamase was revealed by whole-genome sequencing. GRI-1 shared the highest amino acid identity with RIC-1 and OXY-type β-lactamases (76-80%). Analysis of six further publicly-available L. grimontii draft genomes deposited in NCBI revealed that bla GRI-1 was always present. Core-genome analysis indicated that LG-KP-E1-2-T0 was unique from other strains. We provided the first complete genome of L. grimontii and new insights on its chromosomal β-lactamases.