He has received Honorary Degrees from Iona College, New Rochelle, New York (1997) Mount Aloysius College, Cresson, Pennsylvania (2001) and DePaul University, Chicago, Illinois (2011).
Mullan has been published in The Irish Times, the Irish Independent, Ireland on Sunday, the Sunday Tribune, The Examiner, Magill Magazine, la Repubblica, The Times (London), The Guardian, Journal do Brasil and Irish America.