St Helens On 9 February 2017, Richardson made his
Super League début for
St Helens against the
Leeds Rhinos. In October 2017, he signed a new three-year deal at St Helens, with the option of a further year. Richardson was ever-present for the Saints in 2018, making 34 appearances and scoring 6 tries, 147 goals and 7 drop goals. His outstanding personal season saw him named in the
2018 Super League Dream Team.
Sheffield Eagles (dual registration) In July 2017, having featured just four times in his first season at professional level, Richardson played for
Championship outfit
Sheffield Eagles through their new
dual registration deal with St Helens. In his only appearance, he scored a try and converted seven goals.
Leigh Centurions (dual registration) Richardson made 6 appearances for the
Leigh Centurions in the
Championship at the beginning of the 2019 season, kicking 9 goals.
Castleford Tigers In October 2019, the
Castleford Tigers announced the signing of Richardson on a three-year deal. He arrived following the departure of
Luke Gale, to partner
Jake Trueman in the halves. Head coach
Daryl Powell said, "He has a sharp rugby mind alongside his ability to kick the ball in a special way both for goal and tactically." He scored his first try for the Tigers against
Hull Kingston Rovers on 27 February, for an individual haul of 16 points. Richardson made a total of 16 appearances throughout the
COVID-disrupted season, scoring 2 tries, 54 goals and 1 drop goal. In round 19 of the
2022 season, Richardson scored a try, kicked five goals and one drop goal in Castleford's 35–22 victory over the
Warrington Wolves. On 9 August 2022, Richardson signed a two-year contract extension to remain at Castleford until the end of the 2024 season. Weeks later, however, he sustained a torn
ACL and
MCL against the
Salford Red Devils. This serious injury caused him to miss the remainder of 2022, as well as the entire 2023 season. After 18 months on the sidelines, Richardson returned to training for
2024 pre-season.
Hull Kingston Rovers (loan) On 9 May 2024,
Super League club
Hull Kingston Rovers announced that they had signed Richardson on a year-long loan deal.
Hull Kingston Rovers On 23 Aug 2024 it was reported that he had signed for
Hull Kingston Rovers in the
Super League on a 2-year deal from the 2025 season. On 20 February 2025, after an initial 2-week loan to
Huddersfield Giants was announced, he was recalled early by
Hull KR, after playing just one game for the Giants.
Salford Red Devils (loan) On 24 June 2025 it was reported that he had signed for
Salford Red Devils in the
Super League on a 2-week loan
York Knights (loan) On 8 August 2025 it was reported that he had signed for
York Knights in the
RFL Championship on loan until the end of the 2025 season ==International career==