In 2017, Seyfarth joined the Wests Tigers Jersey Flegg team. He was named their best player in 2018, going on to play for the New South Wales under-18s team. The next year, he progressed to NSW's under-20s team.[4]
On 27 July, it was announced that Seyfarth would be ruled out for an indefinite period after suffering a MCL injury.[6]
Seyfarth played a total of 12 games for the Wests Tigers in the 2021 NRL season as the club finished 13th and missed the finals.[7]
2022
Seyfarth played a total of 17 matches for the Wests Tigers in the 2022 NRL season as the club finished bottom of the table and claimed the wooden spoon for the first time.[8]
2023
Seyfarth played a total of 14 games for the Wests Tigers in the 2023 NRL season as the club finished with the wooden spoon for a second straight year.[9] At season's end, he remained without a contract and was linked to the Canterbury-Bankstown Bulldogs before re-signing with Wests for a further two seasons.[10]
2024
Seyfarth played 23 games for the Wests Tigers throughout the 2024 NRL season as the club finished with the Wooden Spoon for a third consecutive year.[11]