The antibacterial and antioxidant potentials of methanolic extracts of Ailanthus altissima Swingle leaves were evaluated. Antibacterial activity was tested in vitro by agar disk diffusion method against 11 (six gram-positive and five gram-negative) foodborne bacteria. The methanol extract and its different polar subfractions inhibited significantly the growth of all six gram-positive bacteria: Listeria monocytogenes (ATCC 19116, ATCC 19118 and ATCC 19166), Staphylococcus aureus (ATCC 6538 and KCTC 1916) and Bacillus subtilis ATCC 6633 and two gram-negative bacteria: Pseudomonas aeruginosa KCTC 2004 and Escherichia coli ATCC 8739. The zones of inhibition of methanol extract and its derived different polar subfractions against the tested bacteria were found in the 12.1–23.2 mm range and the minimum inhibitory concentration values were recorded between 62.5 and 500 µg/mL. Antioxidant activity was evaluated by using 1,1-diphenyl-2-picrylhydrazyl assay. The free radical scavenging activity of ethyl acetate (EtOAc) fraction was superior to all other fractions (IC50 = 16.45 µg/mL) and was higher than synthetic antioxidant butylated hydroxyanisole (IC50 = 18.27 µg/mL). Furthermore, the amount of total phenolic compounds was determined and its content in EtOAc fraction (12.25%) was the highest compared with other extract or fractions.