Dee ihe na-aga n'ihu maka paragraf a - Ebe ọ bụ na ọ na-egwuri egwu maka England U16 na 2011, O mere ka ọ bụrụ onye mbụ na Republic of Ireland U19 na Septemba 2014, na mmeri 1<unk>0 megide Netherlands U19. Na 4 Septemba 2015, o mere egwuregwu mbụ ya maka Republic of Ireland U21 na mmeri 4-1 megide Qatar U23 na egwuregwu enyi na Gigg Lane. Na 25 Machị 2017, Cullen bụ onye isi ndị Republic of Ireland U21s iji merie mmeri 1<unk>0 meriri Kosovo U21 na UEFA Under-21 Championship Qualifier
Ọ dị mma.