Advanced sequencing technologies and improvements in bioinformatics have provided a new way to study plant-associated microbial communities, including the use of host genomic sequencing. Our study focuses on the leaf microbiome of basin big sagebrush (Artemisia tridentata subsp. tridentata), a foundational shrub of western North America. We analyzed Illumina shotgun sequences from sagebrush leaves to investigate the metagenomes of leaf-associated microbes that were sequenced alongside their plant hosts. We aimed to profile the leaf microbiome across different sample sources (magenta box, greenhouse, and field/wild), reconstruct metagenome-assembled genomes (MAGs) where possible, and investigate functional gene annotations of the resulting MAGs, specifically with regard to the potential metabolism of sagebrush chemicals. To achieve this, Illumina shotgun sequence reads (containing both host and associated microbial reads) were mapped to the reference genomes of Artemisia tridentata, Artemisia annua, and the human reference genome to remove plant host and human-associated sequences. Host-cleaned reads were then analyzed using microbial metagenomics techniques. Taxonomic profiling revealed that Phyllobacterium and Sphingomonas were the most abundant microbial genera in greenhouse-grown plants, with very little variation among the samples. Wild, field-collected samples were much more variable and were dominated by Klebsiella and Aureobasidium species. From the co-assembly of greenhouse samples, we reconstructed two high-quality MAGs (a Phyllobacterium species and a Sphingomonas species) with >98% completion and <1% contamination. Functional annotation of these MAGs uncovered genes associated with the degradation and metabolism of camphor and other essential oils such as pinene, geraniol, and limonene, which are part of sagebrush leaf chemistry.