Agnew was brought up a Roman Catholic and held nationalist views.
However his politics were also leaning towards labourism, and he had clashes with more conservative Catholic politicians.
He formed the Armagh Employed and Unemployed Association in 1932, and the following year set up a local branch of the Northern Ireland Labour Party.
[2] He won a seat on Armagh County Council in 1939 from Nationalist Senator Thomas McLaughlin.
[1] Agnew lost his Parliamentary seat at the 1945 general election.