Sullivan made five appearances for St. George Illawarra in the 2021 NRL season as the club missed out on the finals by finishing 11th on the table.[3]
2022
Sullivan played nine games for St. George Illawarra in the 2022 NRL season as the club finished 10th on the table and missed the finals.[4]
2023
In round 10 of the 2023 NRL season, Sullivan scored two tries for St. George Illawarra in their 16-18 loss against the bottom placed Wests Tigers.[5]
In July 2023, Sullivan toured the Wests Tigers facilities after he was given permission to speak to other teams.[6]
On 17 August 2023, Sullivan was released from the final years of his contract to sign with the Wests Tigers on a four-year deal.[7]
2024
Sullivan played nine games for the Wests Tigers throughout the 2024 NRL season as the club finished with the Wooden Spoon for a third consecutive year.[8]
On 20 December, Sullivan was released by the Wests Tigers. The clubs CEO Shane Richardson said to the media “The only reason we’ve let Jayden go is because you can't have him on that money when we’ve signed Jarome Luai". On the same day, Sullivan signed a contract to join South Sydney ahead of the 2025 NRL season.[9]
2025
On 3 September 2025, it was reported that Sullivan had signed a full time deal with South Sydney for the 2026-27 seasons and would not be returning to the Wests Tigers. Sullivan played 13 matches for South Sydney in the 2025 NRL season which saw the club finish 14th on the table.[10][11][12] On 16 October, the Rabbitohs confirmed the two year extension for Sullivan, marking a full time move to the club.[13]
On 12 January 2025, Sullivan received praise after he helped rescue members of a family who were kayaking in Lake Illawarra, Sullivan helped while a rescue team was making their way over to finish off the rescue.[15]
