Walcott inspired the Gunners to an astounding comeback at the Madejski Stadium, scoring three times to help Arsenal recover a four-goal deficit to beat the Royals in a 12-goal League Cup thriller.
Wenger insisted that he has total faith in Walcott's ability and desire to fight for Arsenal despite continued speculation over his long-term future.
He told BBC Sport: "Despite the fact that we have not sorted out his contract Theo has been extremely professional.
"I think he cares about the club and is 100% professional and I am very proud of his performance tonight."
Walcott is Arsenal's top scorer in all competitions this season, with his Reading hat-trick taking the England international's goal tally to seven.