Cannabis sativa, a versatile plant containing over 150 cannabinoids, is increasingly valued for its medicinal properties. It is classified into hemp and marijuana based on its Δ9-tetrahydrocannabinol (Δ9-THC) content. The objective of this study was to optimize cannabinoid production in hemp within a vertical farming system by investigating the effects of methyl jasmonate (MeJA) on plant growth and specific cannabinoid contents. After propagating hemp plants, they were treated with various concentrations of MeJA (0, 100, 200, and 400 μM). Plant growth parameters, glandular trichome (GT) density, and the contents of specific cannabinoids—cannabidiolic acid (CBDA), cannabidiol (CBD), tetrahydrocannabinolic acid (THCA), and Δ9-THC—were analyzed. The results showed that MeJA treatment decreased plant height and leaf area while increasing GT density and the synthesis of CBDA and THCA at lower concentrations. Specifically, treatment with 100 μM MeJA provided optimal conditions for enhancing cannabinoid production while controlling plant height, which is advantageous for vertical farming. These findings suggest that precise application of MeJA in controlled environments can increase yields of valuable cannabinoids with efficient use of space, thereby enhancing the commercial and medicinal value of hemp.