The German is now Arsenal's first choice in goal ahead of Petr Cech after sitting on the sidelines earlier in the season.
Leno was very open about struggling to cope with his move to the Premier League when he first arrived, due to the change in style of football.
"The biggest difference is the speed of the game and also the style of the game.
"Physically it is strong and the referees don't whistle for every contact, I like this way, but it needed a little bit of time because in Germany you are always protected by the referee, but here nobody protects you and you have to get used to it."
Leno also said that he needed time to settle in his new surroundings after departing Leverkusen following seven seasons with the club.
He added: "Arsenal is my second professional club in my career, and it was clear that it needed a little bit of time, but now I am settled in the club and I feel at home here.
"I get confidence from my team-mates, everybody accepts my personality and my quality and, as a goalkeeper, that is very important to have that confidence. I feel very comfortable in this team."
Arsenal are currently going through a transition period after the departure of Arsene Wenger and the arrival of Unai Emery, and Leno believes the changes at the club have affected everyone.
"Many things in the club have changed - new manager, some new team-mates and we play in a different way. For me and the team we needed time to try and trust each other and get a feeling for me
"At the beginning, we had problems with many things - to play from the back and defend our goal but it was normal.
"The manager said we needed time and confidence because last season was not the best season of the club.
"We improved a lot and our defence is much better than before."