Clifford wrote a number of poems and plays, including "The Great Pacificator", which was staged at the Abbey Theatre, Dublin, in 1947. Clifford is best remembered for his poem, "The Boys of Barr na Sráide", which was named after a street in Cahersiveen. The poem recalls the life of his boyhood friends starting from when they were young children through to the Black and Tan period, and up to the civil war. The poem speaks of the Irish tradition of "hunting for the wran" (wren), a small bird, on St. Stephen's Day, 26 December. Later set to music, the song has been recorded by numerous traditional and folk singers including Christy Moore and Tim Dennehy.