In 1993, on his 17th birthday, Cunningham signed for his hometown club
St Helens from
Wigan St Judes. He made his début in the
1994–95 Rugby Football League season, and soon established himself as a world class hooker, renowned for his dynamic running from
dummy half and ability to poach tries from short distances. He represented both
Great Britain and
Wales in international matches, qualifying for Wales because of a Welsh grandfather. Keiron Cunningham played , and scored a
try in
St. Helens' 16-25 defeat by
Wigan in the
1995–96 Regal Trophy Final during the
1995–96 at
Alfred McAlpine Stadium,
Huddersfield on Saturday 13 January 1996. Cunningham played for St Helens at hooker in the
1996 Challenge Cup Final, scoring a try in the second half of the match and helping his team to a 40-32 victory over the
Bradford Bulls. At the end of 1996's
Super League I, Cunningham was named at hooker in the 1996
Super League Dream Team. Cunningham played for St Helens at in their
1999 Super League Grand Final victory over the
Bradford Bulls. Also in 1999 he was the only British player voted into the World XIII. Cunningham played for St Helens at in their
2000 Super League Grand Final victory against the
Wigan Warriors. As
Super League V champions, St Helens played against
2000 NRL Premiers, the
Brisbane Broncos in the
2001 World Club Challenge. Cunningham played at in Saints' victory. Cunningham played for St. Helens at in their
2002 Super League Grand Final victory against the
Bradford Bulls. Over the course of his career, Cunningham rejected offers from the
Welsh Rugby Union,
England Rugby Union, and from various Australian rugby league clubs, instead choosing to remain with his hometown team. In 2006 Cunningham was named as captain of St. Helens following the persistent injuries and subsequent retirement of
Paul Sculthorpe. Cunningham played for St. Helens at in their
2006 Challenge Cup Final victory against the
Huddersfield Giants. St Helens reached the
2006 Super League Grand final to be contested against
Hull FC, and Cunningham played at , scoring a
try in Saints' 26-4 victory. As 2006 Super League champions, St Helens faced 2006 NRL Premiers the
Brisbane Broncos in the
2007 World Club Challenge. Cunningham played from the interchange bench in Saints' 18-14 victory. He played in the
2009 Super League Grand Final defeat by the
Leeds Rhinos at
Old Trafford. In 2010, Cunningham announced that he would be retiring from rugby league following the culmination of 2010's
Super League XV. 2010 also marked the last year at St Helens'
Knowsley Road ground before moving to a new stadium. It was, in fact, Kieron Cunningham who scored the last try ever at the prestigious ground in his penultimate match. However, despite a memorable 2010 play-offs for Cunningham, there was to be no fairytale ending as his last game ended in defeat against arch rivals the
Wigan Warriors in the
2010 Super League Grand Final. He finished his career with 496 appearances for St Helens, scoring 175 tries. During his career he won five Super League Championships, seven Challenge Cup Winners Medals and two World Club Challenge Winners medals, was named in the
Super League Dream Team on six occasions, and in July 2007
Rugby League World magazine ranked him as the greatest player of the
Super League era. Following a supporters' poll featuring the likes of
Tom van Vollenhoven and
Alex Murphy, Cunningham was chosen to be cast as a bronze statue outside of
Langtree Park.{{cite web|url=http://www.sthelensstar.co.uk/news/9311164.Cunningham_statue_moves_to_new_stadium/ ==Coaching career==