The family surname came from Michael O'Neill, who emigrated from County Cork in Ireland to Uruguay in 1837.[3]
Club career
O'Neil signed a contract with Peñarol in December 2021, to last until the end of July. He was signed due to injuries to Juan Manuel Ramos and Valentín Rodríguez.[4] Days later, he had his first involvement with the first team, remaining an un unused substitute in a 3–1 home win over Sud América on the final day of the Uruguayan Primera División season. [5]
O'Neil made his debut on 21 May 2022, playing in a 1–0 home win over Boston River when Ramos was injured after 18 minutes.[2] Four days later he played the full length of a 2–1 win over Colón of Argentina in the group stage of the Copa Libertadores, also at the Estadio Campeón del Siglo.[6]
O'Neil's contract at Peñarol expired in July 2022 and he trained with Unión de Santa Fe in Argentina for six months without gaining a contract under compatriot manager Gustavo Munúa, eventually returning to his homeland's top flight with Fénix in February 2023.[7] On 23 August that year he returned to Unión on a contract until the end of 2025, on a free transfer. He was not chosen by manager Kily González during an eventually successful fight against relegation, and missed several games due to involvement with the Uruguay under-23 team. In December 2023, he was released.[8][9]
O'Neil was part of the Uruguay under-23 squad at the 2023 Pan American Games in Chile. In the fifth-place playoff against Colombia, he came on as a late substitute and scored the first attempt as his country won in a penalty shootout after a goalless draw.[12]