Career
He also represents the Republic of Ireland at under-21 level Born in Westcliff-on-Sea, Cullen was first included in a West Ham matchday squad for their Premier League fixture against Arsenal at the Emirates Stadium on 14 March 2015, remaining an unused substitute as they lost 3–0. He was also called up and unused on 9 May, as West Ham lost 1–0 at Aston Villa.
On 2 July 2015, he made his first-team debut for the club in a 3–0 home victory over Lusitanos of Andorra in the Union of European Football Associations Europa League first qualifying round first leg, replacing Joey O"Brien after 60 minutes.
He started in their 1–0 victory in the second leg a week later, making way for Amos Nasha after 63 minutes. He signed on loan for Bradford City in February 2016.
In March 2016 his loan was extended until the end of the 2015-2016 season. Having already played for England at youth level, in September 2014 Cullen made his debut for Republic of Ireland U19 in a 1–0 victory against Netherlands U19.
On 4 September 2015 Cullen made his debut for Republic of Ireland U21 in a 4–1 victory against Qatar U23 in a friendly at Gigg Lane.
