Early career Simpkins begun his career playing rugby union for Rotorua Boys High School first XV. He signed with
Super Rugby franchise the
Chiefs when he was 15 and held brief talks with the
Crusaders. He was first spotted by
North Queensland Cowboys scouts at the New Zealand 15s rugby league tournament in Rotorua in 2016. He became a New Zealand Secondary Schools rugby league representative and played for the New Zealand Residents team in 2019 before heading to Australia in 2020. In 2020, he was signed by the North Queensland Cowboys, he played one game with North Queensland feeder club the
Townsville Blackhawks in the under 20s competition. He was brought to the
Wests Tigers on a three-year deal in a player swap deal with
Kane Bradley.
2021 Simpkins began the 2021 season playing for
Western Suburbs in the
New South Wales Cup. Simpkins made his debut from the bench in round 18 of the
2021 NRL season for Wests Tigers in their 42–24 victory over the
Brisbane Broncos at
Lang Park.
2024 Simpkins won the Queensland Cup starting at prop in the
Norths Devils 34-20 grand final win over the
Redcliffe Dolphins. On 20 September, Simpkins signed a contract to join strugglers the
Gold Coast ahead of the
2025 NRL season.
2025 Tuki debuted for the
Gold Coast Titans from the bench in there 28-8 round 15 win against
Manly Sea Eagles , it was his first NRL game in 2 years. ==Controversy==