The Arsenal striker has plundered 20 goals in all competitions in 2013-14 against a backdrop of negative allegations regarding the state of his marriage.
Such a return – Giroud is Arsenal's top scorer – has prompted Wenger to pay tribute to his fellow Frenchman ahead of Sunday's Premier League clash with Hull City.
Wenger said: "It was a bit physical and mental as well with what happened to him, but Olivier is a strong lad with a strong mentality and he is a strong, positive guy.
"He has a great mentality which is what I think got him back.
"He has scored 20 goals. That is a great record and he is working very hard for the team."
Giroud's latest goal for the club was a fine strike in Tuesday's 3-1 home win over West Ham, a result that – coupled with Everton's defeat against Crystal Palace a day later – puts Arsenal in pole position to finish fourth and qualify for next season's UEFA Champions League.
Wenger added: "The quality of the goal gives him confidence again, and it gives him credibility again for people who questioned his ability, so that is important.
"He has improved his finishing, but there is still some room for improvement.
"For example, you expect him to score more headers."
