Gallaher retired from playing after the All Blacks' tour, but remained involved in the sport as a coach and selector. He coached at age group level for Ponsonby and in 1906 succeeded Fred Murray as sole selector of the Auckland provincial team. He was Auckland selector until 1916; over this time Auckland played 65 games, won 48, lost 11 and drew 6. Gallaher did make a brief comeback as a playertravelling as the selector of an injury depleted Auckland team, he turned out against Marlborough at Blenheim in 1909; Marlborough won 8–3. He also played against the Maniapoto sub-union just over a week later. Auckland held the Ranfurly Shield from 1905 to 1913, successfully defending it 23 times. The team struggled to retain the shield during 1912 and 1913 and eventually lost it to Taranaki in a 14–11 defeat. During Gallaher's tenure as selector Auckland inflicted an 11–0 defeat of the touring 1908 Anglo-Welsh side, defeated the New Zealand Māori in 1910, and beat Australia 15–11 in 1913.