A former Ysgol y Strade pupil in Llanelli, Steff began his regional career with Scarlets U16s before graduating through the ranks. Was named as Wales U20s captain for the 2014 Six Nations and was part of the U20s squad that reached the final of the Junior World Championship in 2013. Has recovered from a serious knee injury to become a respected leader within the squad and has captained the side on numerous occasions over the last couple of seasons. On the verge of a 100 appearances in a Scarlets jersey.