[5] He made his Hull Kingston Rovers debut in a Challenge Cup fourth round tie in April 2008,[6] and signed a two-year contract until the end of the 2010 season in June 2008.

[7] After a fine season in 2010 in which Watts played 26 of 27 Super League matches, he was called up to the England training squad for the Four Nations Championship in September 2010,[8] and awarded the 2010 Albert Goldthorpe Rookie of the Year Medal.

[11] Hull coach Peter Gentle said: "Liam is certainly a promising player for the future and we are looking forward to helping him realise his potential".

[18] Hull had agreed a fee with Championship side Toronto Wolfpack, but Castleford's "last-minute significant offer" saw him return to Wheldon Road.

Watts had an outstanding personal season in 2019, playing in all but 2 of Castleford's games and earning a place in the Super League Dream Team.

[25] In the opening match of the 2024 season, Watts was controversially sent off for a high tackle on Wigan's Tyler Dupree,[26][27] under new laws introduced to Super League.