[4] He returned to his hometown club Dundalk in September 2014, initially playing with their under 19 side in the League of Ireland U19 Division before gradually breaking into the first team squad.
[5] Dundalk first team manager Stephen Kenny offered O'Connor his first professional contract which he signed on 22 February 2015, aged just 16 years old.
[7] He went on to make two more first team appearances in the 2015 season, both in the Leinster Senior Cup, including starting the final which was a 3–1 over Shamrock Rovers at Oriel Park.
[10] He made his League of Ireland Premier Division debut against the same opposition, replacing David McMillan late on as his side left Dalymount Park victorious this time, winning 2–0.
[11] On 26 August 2016 he made his European debut, coming off the bench in a 1–1 draw with Legia Warsaw in the UEFA Champions League play-off round.
[4] During the season O'Connor faced Burnley in a friendly and impressed manager Sean Dyche enough to be on the verge of signing him for the Premier League side.
[22] With O'Connor still in contract until the end of the season with Shamrock Rovers, they opted to send him on a 6 month loan to Finn Harps who were chasing promotion from the League of Ireland First Division, in order to find more playing time.
[23] His debut came in the opening game of the season at home to Shelbourne, starting up front alongside his brother Ciáran O'Connor and scored his sides only goal in a 1–1 draw.
[26] As he had done with Shamrock Rovers, O'Connor endeared himself to the fans early, by scoring a crucial goal in the derby when he equalised in the 86th minute away to Cliftonville to salvage a point for his 10 man Linfield side.
[32] O'Connor signed a loan deal with League of Ireland Premier Division side Waterford on 13 July 2019 until the end of the 2019 season.
[45][46][47][48][49] O'Connor made his Ross County debut on 10 November 2020, coming off the bench for Harry Paton in a 4–1 away win against Elgin City in the Scottish League Cup.
[55] He departed the club at the end of the season with Glentoran manager Mick McDermott publicly stating that he was interested in signing him having previously tried to do so while he was a Linfield player before their transfer bid was declined.
[70] He made his debut coming off the bench for Aaron Drinan in the 52nd minute of a 1–0 win over the Republic of Ireland Ametuer squad at Whitehall Stadium.