[1][4] He also played in the Scottish League for Partick Thistle and St Mirren.
[3] In March 1916, in the middle of the First World War, Callaghan enlisted in the British Army.
[5] He served as a private in the Somerset Light Infantry and the London Regiment.
[3] Whilst maintaining an artillery gun, Callaghan was killed while serving with the 1st/20th Battalion, London Regiment, part of the 47th (1/2nd London) Division, by German shellfire during a trench raid at Hill 60, Belgium on 20 February 1917.
[2] This biographical article related to association football in England, about a forward born in the 1880s, is a stub.