He gained several nicknames but was mostly known as "The Fox" for his cunning and finesse. Widely considered one of the most influential personalities in American organized crime, Torrio impressed authorities and chroniclers for his business acumen and diplomatic skills.
The US Treasury official Elmer Irey considered him "the biggest gangster in America" and wrote, "He was the smartest and, I dare say, the best of all the hoodlums. 'Best' referring to talent, not morals." Virgil W. Peterson of the Chicago Crime Commission stated that his "talents as an organizational genius were widely respected by the major gang bosses in the New York City area." Crime journalist Herbert Asbury affirmed: "As an organizer and administrator of underworld affairs Johnny Torrio is unsurpassed in the annals of American crime; he was probably the nearest thing to a real master mind that this country has yet produced".
Torrio was born in Irsina (then known as Montepeloso), Basilicata, in Southern Italy, to Tommaso and Maria Carluccio originally from Altamura, Apulia. When he was two his father, a railway employee, died in a work accident, and Torrio shortly after emigrated to New York City with his widowed mother in December 1884. She later remarried.
His first jobs were as a porter and bouncer in Manhattan. While he was a teenager, he joined a street gang and became its leader; he eventually managed to save enough money and opened a billiards parlor for the group, and from there grew illegal activities such as gambling and loan sharking. Torrio's business sense caught the eye of Paul Kelly, the leader of the infamous Five Points Gang. Torrio's gang ran legitimate businesses, but its main concern was the numbers game, supplemented by incomes from bookmaking, loan sharking, hijacking, prostitution, and opium trafficking. Al Capone, who worked at Kelly's club, admired Torrio's quick mind and looked to him as his mentor. Torrio, in turn, greatly admired Kelly, who knew much about organized crime culture; Kelly convinced the younger man to dress conservatively, stop swearing, and set up a front as a legitimate entrepreneur.
Capone had belonged to the Junior Forty Thieves, the Bowery Boys and the Brooklyn Rippers; they soon moved up to the Five Points Gang. Torrio eventually hired Capone to bartend at the Harvard Inn, a bar in the Coney Island section of Brooklyn owned by Torrio's business associate, Francesco Ioele (also known as Frankie Yale).