The 27 year old winger scored during the club 3-0 victory over the Chelsea on Saturday now hails by his manager.
The Frenchman has praises the Englishman as a Different Footballer after the winger continued his impressive start against Chelsea.
Wallcot scores his third goal for the Gunners this season as the Gunners ran riot on the Emirates, eventually they won by 3-0.
The 66 year old was pleased with the England international performance, as Arsenal won a first league win over the Blues since October 2011.
"You cannot question his performance," Wenger told a news conference.
"But I believe more the change in Theo Walcott is his attitude to this season. He's ready to fight, commit and straight away he gets the crowd behind him.
"Theo Walcott of that stature is a completely different player."
The Chilean Alexis Sanchez and the German Mesut Ozil were also on the score sheet, they scored in the first half, where they showcase a wonderful style of football.
"I'm hungrier because I know I don't have 20 years in front of me," the Frenchman said.
"Also I feel more responsibility, you're not 20 years somewhere and you don't care about things.
"I'm more conscious of what Arsenal is all about so I think the weight of keeping people happy and making people happy is heavier than when I arrived."