[3][4] He lost to hard hitting Jack McGee in Boston on December 19, 1884, in a fast second round knockout before a crowd of around 100.

[5][3] Black boxer Walter Edgerton, better known as "Kentucky Rosebud" fell to Duffy in a four round points decision in Philadelphia on July 28, 1886.

The fit black boxer stood up to considerable punishment in the short contest and used agility and speed to avoid many of the blows he received in the first round.

Duffy dominated the first two rounds, knocking his opponent to the mat in the first, and though the fourth began cautiously, he backed Edgerton against the ropes inflicting a rain of blows.

The Times of Philadelphia felt Duffy had the better of the bout by a shade, but the referee called a draw to the close contest.

Making it clear the match was nearing an end, Duffy dominated the third, punching Murphy across the ring, with little return, and putting him down twice for brief counts.

[11] In a bout with Charles Gleason, on January 7, 1889, Duffy was given "the fight of his life", in a ten round points decision in Boston.

The official ruling was a draw, but Gleason proved a hard hitter and a clever sparrer and was game throughout the match.

According to one source, the actual fighting took place in an old barn with a ring, six miles south of Washington, D.C.[14][15][16][17] He secured the world welterweight title against British-born Australian champion Tom Meadows on March 29, 1889, in an exhausting 45 round bout at San Francisco's California Athletic Club.

One reporter wrote that spectators lost interest when both fighters occasionally ceased boxing in the latter rounds, with Meadows leaning on a post, and Duffy folding his arms in the center of the ring.

[7] Just over a year after his win over Tom Meadows, while still reigning champion, he died of tuberculosis, then known as consumption, on July 10, 1890, at the age of 25, at his home at 5 Endicott Court in North Boston.

Friends attributed his health problems to his boxing career, particularly his last brutal bout with Tom Meadows where he received frequent blows to his chest.