Having made the 27-year-old striker his fourth capture of the summer in a club record £7.5million deal, Curbishley told whufc.com: "I'm really pleased to have signed Craig.
"He is keen to prove to lots of people what he can do, having not been given much of a chance at Liverpool. They have moved on now, but so has Craig, and I'm certain that we are going to see the best of him at West Ham.
"He has an opportunity now to cement some roots and show everybody what a good player he is. I'm sure he will strike up a good rapport with the fans, because he tries his hardest in every match and desperately wants to win.
"People have raised eyebrows at the fact that he has played for a few clubs but, if you actually look at his record, it isn't anything out of the ordinary.
"He was at Norwich as a young boy, then went to Coventry who were relegated in his first season. At Newcastle he had a fantastic start under Bobby Robson, but then didn't see eye-to-eye with Graeme Souness, and so spent a short spell at Celtic.
"He did fantastically well at Blackburn, and then Liverpool came in to activate the release clause he had. Every move has been to better himself, and now he is coming to us in the prime years of his career.
"He is hungry to do well and I'm sure he will be a great asset to us. Along with Scott Parker, Julien Faubert and Richard Wright, his arrival has added further strength to the squad, and we are all looking forward to the new season."