A product of Coleg y Cymoedd, Dane came through the Academy system at Cardiff Rugby and was capped at Wales U18s and Wales U20s level. Blacker joined the Pontypridd squad as one of the Cardiff Rugby Academy allocation for the 2016 - 2017 season. Impressing in the Welsh Premiership he was added to Wales U20 side in January 2017 that would compete at the U20 Six Nations tournament.
The Pontypridd born scrum half made seven appearances for the Blue and Blacks either side of a brief loan spell with the Dragons where he made two appearances in 2017, scoring the one try on debut. Blacker featured for Wales 7s on the world series circuit and joined the Scarlets ahead of the 2019-20 campaign. He was the side's top try-scorer in 2020-21, pushing him into international contention, being named in Wayne Pivac's Welsh squad for the 2022 Autumn Nations Series despite not making his debut he continued that form into the 2022/23 season. Overall, Blacker made 53 appearances for Scarlets scoring an impressive 15 tries in his four seasons in West Wales.
Ahead of the 2023/2024 season scrum half Blacker decided to link up with his former attack coach at Scarlets and current Dragons Head Coach Dai Flanagan in Newport after signing a long-term deal with the Men of Gwent.