Background The composition and activities of essential oil of common sage from Saudi Arabia have not yet been reported. Objectives To analyze the composition and antibacterial and antioxidant activities of essential oil from leaves of the common sage Salvia officinalis L. from Abha, Saudi Arabia. Methods Essential oil was extracted from the leaves of S. officinalis by hydrodistillation, and its composition was analyzed using gas chromatography and mass spectrometry. Phenolics and flavonoids were determined using gallic acid and quercetin standards. Antioxidant activity was determined using a 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. Activity against various gram-positive and gram-negative bacteria was determined by disk diffusion and microdilution. Results The yield of essential oil was 3.24 ± 0.55% (w/dry weight). Major compounds identified were camphor (20.3%), 1,8-cineole (15.0%), α-thujone (14.9%), viridiflorol (9.9%), carvone (6.2%), and β-thujone (5.7%). Phenolic content was 134.3 ± 17.61 μg/mL and flavonoid content was 119.5 ± 18.75 μg/mL. Antioxidant IC50 was 970 ± 5.5 μg/mL. The highest gram-positive antibacterial activity was for Bacillus subtilis and the highest gram-negative activity was for Escherichia coli. Minimum inhibitory concentrations ranged from 62.2 ± 3.9 to 1398.1 ± 50.7 μg/mL for gram-positive bacteria and from 323.4 ± 69.5 to 968.4 ± 120.6 μg/mL for gram-negative bacteria. Minimum bactericidal concentrations ranged from 120.3 ± 7.6 to 1387.4 ± 161.8 μg/mL for gram-positive bacteria and from 386 ± 8.3 to 1225.2 ± 100.9 μg/mL for gram-negative bacteria. Conclusions Essential oil of S. officinalis L. from Abha, Saudi Arabia, showed compositional, antioxidant, and antibacterial properties generally consistent with essential oil of S. officinalis L. from other locations as reported in the literature.