Tuilagi played for St. Helens at second-row in their 1999 Super League Grand Final victory over Bradford Bulls.
Having won the 1999 Championship, St. Helens contested in the 2000 World Club Challenge against National Rugby League Premiers the Melbourne Storm, with Tuilagi playing from the interchange bench in the loss.
He also played for St Helens from the interchange bench, scoring a try in their 2000 Super League Grand Final victory over Wigan Warriors.
He left St. Helens in June 2000 and signed for Leicester Tigers, also making his return to the Samoa national side.
He was also selected to tour New Zealand, but was prevented from doing so by an injury, which also denied him a place in national side's world cup squad.