Joseph Paul O'Brien-Whitmarsh (born 11 May 2005) is an Irish professional footballer who plays as a midfielder for club Southampton.
He started his career at Fermoy F.C. before joining Cork City academy in 2019. He signed a professional contract with Cork in 2021. He made his senior debut for Cork City in March 2023 and played for the club in the 2023 League of Ireland Premier Division.
He joined Premier League side Southampton in January 2024 from Cork City for an undisclosed fee. He was included in Southampton's match-day squad for the EFL Cup tie against Cardiff City on 28 August 2024, making his debut as a second-half substitute.
On 3 February 2025, O'Brien-Whitmarsh joined League Two side Accrington Stanley on loan for the remainder of the 2024âÂÂ25 season. He made his debut for the club on 8 February 2025 in a 0âÂÂ0 home draw with AFC Wimbledon. On 4 March 2025, he scored his first goal in English football during a 2âÂÂ0 home win over Milton Keynes Dons. The following week, he scored another two goals, credited with a brace in a 5-0 home league win over Newport County on 11 March 2025.
He has been capped by the Republic of Ireland at under-19 level. In November 2024, he received his first call up to the Republic of Ireland U21 squad for their two friendlies against Sweden U21 in Marbella, Spain. He made his debut in a 2âÂÂ0 defeat to Sweden on 14 November 2024.
He is the son of former Cobh Ramblers striker Paul Whitmarsh.