"Big" Jim O'Leary (c. 1860-1926) was an early illegal gambling racketeer in Chicago and formed one of the cities first gambling syndicates.

One of Chicago's early crime figures James O'Leary was born outside Chicago to Patrick and Katherine O'Leary, the woman who's cow supposedly started the Great Chicago Fire of 1871, around 1860. O'Leary began working for local bookies as a teenagter eventually opening Long Beach, Ind. , an off-track betting resort by the 1880s however it soon closed due to bankruptcy. O'Leary soon opened another betting parlor on South Halstead Street which he designed to include Turkish baths, a restaurant, billiard room, and a bowling alley, as well as the detailed race track results and other betting information to become one of the countries most prominant resorts by the 1890s. In 1904 O'Leary began operating illegal gambling on Lake Michigan with the steamship The City of Traverse however without police protection the ship soon went out of business in 1907 due to repreated police raids after the ship had docked. O'Leary however refused to bribe police having his businesses fortified including the construction of an iron and zinc layered oak door to his resort which were supposedly "fire proof, bomb-proof, and police-proof." After Chicago crime lord Michael Cassuis MacDonald 's death that same year O'Leary gained exclusive control of gambling operations in Chicago's Southwest Side based in around the Union Stockyards . O'Leary, who had been delivering whiskey to Colosimo's restaurant arranged by Johnny Torrio, was suspected of being involved in the murder of James Colosimo on May 11, 1920 however there were no charges brought against him. By the time of his death in 1926 O'Leary had become a millionare several times over.

Further reading

• Jay Robert Nash, Encyclopedia of World Crime (K-R) Vol. III, Crimebooks Inc., 1990, hardcover, 1,000 pages (853-1750)