Born in Belfast,Sykes began his career with Glenavon. In December 2017 he was linked with a transfer away from the club. In February 2018 he signed a new contract until the end of the 2018–19 season. In March 2018 he was described by a journalist as "one of the most outstanding young prospects in the Irish League".
In January 2019 he signed for English club Oxford United, making his debut on 8 January 2019 in the EFL Trophy. He scored his first goal for Oxford against Millwall in the EFL Cup on 27 August 2019, and his first league goal in a 2–1 victory over AFC Wimbledon on 29 December 2019.
Sykes scored Oxford's consolation goal in their 2–1 defeat to Wycombe Wanderers in the 2020 EFL League One play-off Final at Wembley Stadium.
He has also played for Northern Ireland at under-18, under-19 and under-21 youth levels. He made his debut for the under-21 side in September 2016, in a 2–0 defeat to Macedonia and as of 28 January 2019 had 11 caps and 2 goals.
He received his first call-up to the Northern Ireland senior team in May 2019. He was called up again in September 2019. In August 2020 he informed the Irish Football Association (which governs football in Northern Ireland) that he no longer wished to be considered for their squad, instead opting for the Republic of Ireland. In March 2022, he was named in Stephen Kenny's Republic of Ireland squad for forthcoming friendly matches.
Taken from Wikipedia