[2][3][4][5] He attended St Joseph's College, Ballinasloe,[6] and entered UCD in October 1911.

Two years later he was awarded his MA degree, and he worked as an assistant lecturer in Greek from 1918 to 1919 and 1920 to 1922.

In 1917 he won a National University of Ireland (NUI) travelling studentship in Classics and used it to study in the Sorbonne, British School at Athens and Berlin from 1919 to 1921.

[7] Tierney was elected a Cumann na nGaedheal Teachta Dála (TD) for Mayo North in a by-election in 1925 and for the NUI constituency in 1927, a seat he held until 1932.

He was an early member of the Army Comrades Association (later known as the Blueshirts) and, along with Ernest Blythe, encouraged Eoin O'Duffy to become the leader.