He won two All-Ireland darts titles with Cork and a European bronze medal playing for Ireland.
[3] O'Shea had his biggest career win at the 2019 World Masters, where he defeated Scott Waites 6–4 in the final.
[5] Originally ranked number 219 in the British Darts Organisation rankings, he rose to number 59 and also earned qualificaton for the 2020 BDO World Darts Championship.
[5][6] At the BDO World Championship, he lost 3–2 to Andreas Harrysson in the preliminary round.
[7][8] He reached his first PDC ranking final in Players Championship 14, losing 7–4 to Michael Smith.