The former Olympique Marseille star told France Football: "I'm so excited!
"I arrived in London on Sunday and had my first training session the day after, before we go on pre-season camp in Austria.
"I have joined an immense club where there's everything to achieve great things. I'm delighted to be part of this new adventure. Arsenal are a reference point."
"He's been decisive," added Nasri. "He represents stability and continuity. We understand we can work on the long term with him. I think he's been at Arsenal for 13 years. It means the world!
"I was looking for that kind of guarantee to advance my career. I didn't want to go to a club, even a legendary one, where everything could change from one day to another.
"I know Arsene Wenger's going to help me improve. He has had a lot of success with other French players, especially youngsters he helped blossom."