 After teaching for eighteen years at the Synge Street CBS in Dublin, MacManus joined the staff of Radio Éireann (precursor to RTÉ, the Irish national broadcasting entity) in 1948 as Director of Features.MacManus began writing while still teaching, first publishing a trilogy set in Penal times and concerning the life of the Gaelic poet Donncha Rua Mac Conmara comprising the novels "Stand and Give Challenge" (1934), "Candle for the Proud" (1936) and "Men Withering" (1939).A second trilogy followed which turned its attention to contemporary Ireland