On 2nd April 1917, McSweeney joined Northern Bank and was posted to Dungloe branch.
McSweeney volunteered and enlisted into the North Irish Horse on 29th September 1917 and left the bank on 3rd October 1917.
He saw service in the Home Service prior to being discharged for being under age.
On 13th December he rejoined Northern Bank at Strokestown. Transfers followed to Head Office (1920), Grafton Street (1921), Kingscourt (1927), Head Office (1928), Ball’s Branch (1929), Head Office (1930), Falls (1930) and Oldcastle (1931).
McSweeney retired on 31st March 1962.