Mullan was Director of AFrI (Action from Ireland) 1979–93 during which he and colleagues developed the Great Famine Project. He was one of the first in the Irish world to recognise the approaching 150th anniversary of The Great Famine (The Great Hunger) as "a unique historical moment". AFrI's project helped to generate awareness of the anniversary all over Ireland and throughout the world. Mullan established a "famine walk" in Co. Mayo, commemorating an actual walk of starving Irish peasants in 1848. The walk attracted the attention of ABC, NBC and CBS News during its first three years, 1988–90. The walk continues as an annual event. As part of the project Mullan established several connections with the Choctaw Nation of Oklahoma and was made an Honorary Chief. The Great Famine Project was multi-disciplined and involved publications, documentaries, dramas and commemorative events including the marking of forgotten mass Famine graves containing the sacred remains of thousands of Irish victims.