Arsene Wenger snapped up Giroud from Montpellier, where the striker was part of the team that pipped Paris Saint Germain to the Ligue 1 title.
And he believes that Arsenal can also achieve something big this season even though they are regarded as outsiders.
"It’s true that it was an extraordinary season with Montpellier," Giroud told Arsenal Player. "I won’t ever forget that season because in a footballer’s career, winning the title isn’t forgotten so fast.
"There was a good mentality in the team, good quality, with some good players, and I look forward to finding that quality and spirit with Arsenal - that’s why I chose Arsenal.
"With Montpellier, it wasn’t written that we were going to be champions, so that’s what made it more beautiful. With Arsenal, we might not be favourites, like the Manchester clubs, to be champions.
“We’re outsiders, but I’m convinced that we can do something big. That’s what we did with Montpellier, and I'm proud with what I accomplished there."