Gildea was engaged in the newspaper publishing business from 1910, when he founded the Coaldale Observer. He worked as chairman of the Coaldale Relief Society from 1930 to 1933, and of the Panther Valley Miners' Equalization Committee.
Gildea was elected as a Democrat to the Seventy-fourth and to the Seventy-fifth Congresses. He was an unsuccessful candidate for reelection in 1938, 1940, and 1950.
He then resumed his newspaper work and continued publishing until his retirement in 1972. He also worked as superintendent of the Coaldale State Hospital from 1962 to 1965 and managed a professional football team, the Coaldale Big Green.