Nkufo said he was excited about the challenges ahead of him in MLS and looking forward to getting out on the pitch with his new teammates.
"I am really happy. When I first met with Adrian (Hanauer) and Gary (Wright) I was really impressed with the facilities and really felt that they want me. It was my decision to make and we did the deal and I'm really proud to be a part of this team," he said.
Nkufo said he hopes to do what he does best with the Sounders - score a lot of goals - and wants to bring his best form to Seattle.
"A lot of goals, the next couple of weeks," he added. "I'm going to play in the World Cup. I just finished to play with Twente in the league and I need to be again focused for the World Cup, and the next will to be with the Sounders.
"I hope the best of me, of course. As a striker, they can expect a lot of goals. I need my team players crossing passes but I know what I can do for this team and I'm going to be focused on my skills; what I have done from the past and I wish to do that for the Sounders."