Henry joined his former club on a six-week loan deal that will see him stay at the Emirates until February 26.
In addition to domestic encounters, Arsenal will also take on AC Milan in the Champions League round-of-16 tie in February and Henry is part of Wenger's plans for the first leg.
Speaking to Arsenal.com, Wenger said: "Yes, he will be [in the squad].
"I have given Vito Mannone out on loan to Hull and Thierry will take his place.
"He has good memories of playing in Milan, where he scored three goals against Inter Milan. It is logical [to include him]."
Wenger remarked that the New York Red Bulls striker's return has had a positive impact on the team.
"The players are happy that he is here. It is more to do with the interaction physically in everyday training. Of course, how much he wants it as well," said the Frenchman.
"I was convinced quickly [that he was still capable of playing in the Premier League] but I wasn't sure that he would like the challenge. He knows that somewhere, people will look at how he is doing now."
At the same time, the Gunners' manager played down questions asking if Henry could become part of the coaching set-up at Arsenal in the near-future.
"Let him play first and what he will do one day I don't know. Play as long as you can in life. Life is still long enough after to coach - look at the state I am in, I took up coaching very young!"
The primary reason behind Wenger's decision to bring Henry back was the Africa Cup of Nations, which has seen Gervinho depart for Ivory Coast duty.
And Wenger admitted he was worried about the toll playing in such a high-profile tournament would take on his players.
"It is the equivalent of a player here going to the European Championship. They are under immense pressure," he said.
"It is a different climate [over there]. Usually we have snow in February here, so they come from a big temperature difference. Most of the time, they are dead [afterwards]."
When pressed on who his pre-tournament favourites were, Wenger cast his vote for Ivory Coast.
"Ivory Coast are hot favourites; they have an incredible team. They have a midfield of [Cheik] Tiote, [Yaya] Toure, Gervinho.
"Nobody else has qualified. Cameroon is not there, Nigeria is not there - they are under massive pressure."
Moving back to club matters, the 62-year-old said he would not be looking for a long-term solution to Arsenal's left-back problems. Both Kieran Gibbs and Andre Santos are out with injuries, along with other defensive casualties like Bacary Sagna, Thomas Vermaelen and Carl Jenkinson.
"I do not want to go for a permanent solution because we have to pay all these people as well," said the manager. "But if I can, yes I will get a loan player until the end of the season.
"Vermaelen should be back, not for Swansea [next weekend], but after that."