[2] Jansen signed for Leicester on 23 February 2022,[3] he has previously played for North Otago in New Zealand featuring for them in the 2021 Lochore Cup Final.
[4] Jansen made his Leicester debut on 18 March 2022 in a 36–28 loss to Newcastle Falcons in the Premiership Rugby Cup, and was noted for his ball carrying and tackling.
[5] He made his full Premiership Rugby debut against Harlequins on 23 April 2022, playing number 8 in a 26–20 loss.
[6] Jansen scored his first try for Leicester on 27 September 2022 in a 38-17 win against Wasps in the Premiership Rugby Cup.
On 10 March 2023 Jansen's signature was announced by Connacht on a two-year deal starting in the summer of 2023.