Mark James McGuinness

Mark James McGuinness joined Arsenal's academy at the age of ten and signed his first professional contract there in April 2019, though he never made a senior league appearance for the club. His path to first-team football came through a loan to Ipswich Town in the 2020–2021 season, where he made 24-25 appearances and scored once. In 2021, Cardiff City paid a reported fee of around £2.3 million for the centre-back, and he went on to make 83 league appearances for the Welsh club, scoring five goals. A loan spell at Sheffield Wednesday in 2022–2023 brought 17 league appearances and a goal before he was recalled by Cardiff in January 2023.

McGuinness's move to Luton Town in August 2024 carried a base fee of roughly £6 million, with add-ons potentially pushing the total towards £10 million. He made 48 league appearances for Luton and scored three times. On 1 September 2025, he signed for Sheffield United for a reported £5 million, a fee confirmed by manager Chris Wilder, putting pen to paper on a contract running to 2029. He has since made 29 league and two cup appearances for the club.

McGuinness qualifies for the Republic of Ireland through his father and represented the country at both under-19 and under-21 level, scoring twice in ten appearances for the U19s and once in 13 for the U21s. He made his senior debut for Ireland on 17 November 2024 in a UEFA Nations League fixture against England, and has earned two senior caps to date.