Attell was a member of a Jewish family, but he grew up in an Irish neighborhood. Because of that, he often found himself involved in fights, and according to him, he would get involved in as many as 10 bouts each day as a kid. Attell's father abandoned his family when Attell was 13, and Attell had to find a job selling newspapers to support his family. He used to sell them on the streets and corners, and while selling newspapers, he got a chance to witness the fight between Solly Smith and George Dixon for the world's Featherweight championship. With that, Attell and two of his brothers were convinced that maybe they had a future in boxing.
Attell's first fight was on August 19, 1900, when he knocked out Kid Lennett in two rounds. His mother, who strongly opposed Attell's idea of being a boxer, later became one of Attell's staunchest supporters, even betting on her son to win.
Attell won ten fights in a row by knockout and later moved to Denver, Colorado, where he met Dixon for the world's Feathrweight championship in 1903, when Attell was 18/ He beat Dixon by a decision in fifteen rounds, and became world Featherweight champion. He lost the crown in his second defense, being knocked out in five rounds by Tommy Sullivan. However, he regained the crown from Sullivan by beating him in their rematch by knockout. Attell then went on his streak of 18 defenses in a row. He beat, among others, Battling Nelson and Johnny Kilbane during that streak.
During his time as a world champion, Attell was allegedly involved with mafioso Arnold Rothstein. According to some legends, they became very good friends during this period.
Attell went on to lose his world Featherweight title to Kilbane in 1912, losing by a 20 round decision, in a fight of which Kilbane declared that Attell's handlers put a substance on Attell's glove to make Kilbane blind. According to live witnesses, Attell also tried an assortment of other illegal methods to win the fight.
Attell was involved in one of sport's largest scandals of all time, when he was signaled, in 1920, as the messenger between Rothstein and players of the Chicago White Sox baseball organization, during the planning stages of the alleged fix of the 1919 World Series, also known as the Black Sox scandal. Attell's name made it back to the newspaper headlines, and he along with Rothstein and many White Sox players, were formally accused of many charges, including fixing the event. All were eventually found not guilty but banned from participating in baseball activities. As a consequence, Attell is, alongside Rothstein, Shoeless Joe Jackson and Pete Rose, one of the few people banned from joining the Baseball Hall of Fame and Museum. He was, however, a member of the original boxing Hall of Fame, a member of the Jewish Sports Hall of Fame, the San Francisco Boxing Hall of Fame, and of the International Boxing Hall Of Fame. In the latter, he was inducted as a member of their original class, in 1990.
Attell subsequently denied being involved in any talks about fixing the series, and he alleged that the wrong Abe Attell was accused when he was accused.
Attell had a record of 92 wins, 10 losses, 18 draws and 45 no-decisions, with 51 wins by knockout, making him a member of Ring Magazine's list of fghters with 50 or more knockout wins.