Newcastle boss Alan Pardew today admitted the Magpies could not reach an agreement with their skipper over the length of his new contract.
And Nolan added: "The be all and end all was that this club wanted me and the owners put faith in me and have given me a security of contract. Now it's my time to repay them and hopefully I will do that."
Pardew, a former boss at Upton Park, said: "I would like to thank Kevin for his sterling efforts as a player and captain of this club, especially since I took over last season.
"He displayed admirable leadership qualities and I wish him every success at West Ham. It's a great club and I'm sure he will thrive there.
"We are looking to complete on a number of deals over the next month or so and I am sure with the quality of signings I anticipate coming into the club, we should look forward to exciting times in the upcoming season as we look to establish the club as a genuine force in the top half of the Premier League."