Gallagher became involved in a three-year feud with local bartender William Lennon in 1907, their dispute being over a card game, which resulted in several violent altercations between them. The first incident between the two required Gallagher to have stitches after Lennon had repeatedly slashed his face with a knife. Gallagher later claimed that Lennon had threatened to shoot him on sight and engaged him in several gunfights including an incident in December 1909 when Lennon wounded him in a gunfight between the two.