Upon her return to the United States, O'Beirne-Ranelagh immersed herself in the study of African-American spirituals and slave music, making pioneering broadcasts of such music on station WNYC with her programme "Folksongs for the seven million". Through this she brought the music of Lead Belly to a broader audience, appearing regularly on her radio programme. Towards the end of World War II she met James O'Beirne at Columbia University Library, meeting to record his repertoire of Irish songs. He had fought in the 1916 Easter Rising with The O'Rahilly, and later with the Cork No. 1 Brigade during the War of Independence. Following a period of internment, he had traveled to the United States in 1923 to complete the engineering degree he had started at University College Cork.