Shaw started his career at seven sisters RFC in the Dulais valley at junior and youth level.
[7] Despite being appointed captain at Neath in 1977, Shaw changed codes and signed for rugby league side Widnes in November of the same year.
[citation needed] Almost immediately he was selected for the won caps for Welsh national team against France and Australia in 1978.
The first in the 12–3 victory over Wakefield Trinity in the 1978–79 Challenge Cup Final at Wembley Stadium, London on Saturday 5 May 1979, and two years later he was an substitute in the 18-9 victory over Hull Kingston Rovers in the 1980–81 Challenge Cup Final at Wembley Stadium on Saturday 2 May 1981.
Shaw played right-prop in Widnes' 4-9 defeat by Warrington in the 1977–78 Players No.6 Trophy Final at Knowsley Road, St. Helens on Saturday 28 January 1978, played right-prop in the 16-4 victory over Warrington in the 1978–79 John Player Trophy Final at Knowsley Road, on Saturday 28 April 1979, played right-prop in the 0-6 defeat by Bradford Northern in the 1979–80 John Player Trophy Final at Headingley Rugby Stadium, Leeds on Saturday 5 January 1980.