O'Leary's was founded in 1949 by John J. O'Leary Sr. and his wife Ruth in a one-room office located on Lake Street in Chicago. O’Leary’s is your trusted rental store for portable air comPressors, generators, air tools, light towers, saws, welders, and so much more. Whatever your rental needs are, O’Leary’s is your one-stop-store. All their rentals are available for sale.