As one of the stars of the world game, Sculthorpe secured a lucrative sponsorship deal as the face of Gillette, which at the time was the most lucrative sponsorship deal made by any rugby league player worldwide. In March 2006, Sculthorpe signed a deal with Random House to publish his autobiography, "Man of Steel", which was published in August 2007. Sculthorpe captained St Helens as a in their 2006 Challenge Cup Final victory against Huddersfield. However his time as Great Britain captain was less successful, as he only ever captained the side for 18 minutes. This came in the one off test game at Knowsley Road in 2006 between Great Britain and New Zealand, in which he was forced off after injuring his knee. Sculthorpe returned from the injury and was named man-of-the-match in St Helens' win over Brisbane Broncos in the 2007 World Club Challenge. In September 2007 he signed a new 12-month contract with St Helens which saw him celebrate his testimonial season at the club.