The French boss was delighted that his side were able to secure the Ivorian's services but warned that the forward may not be able to show his true colours immediately
The Cote d'Ivoire international has joined the Ligue 1 club on a free transfer after being released by Chelsea at the end of the season.
Garcia believes that Kalou, together with Marvin Martin, will be quality additions to his side and admitted that signing the Ivorian was not a simple task.
"It was not easy to convince him," Garcia told Lille's website. "He had just won the Champions League.
"I am very satisfied with this signing. We wanted to sign two great players, and we were able to do it.
"It is nice to have them with us already because that will allow us to have four weeks of preparation with just about everyone.
"Kalou is a very good player with the ball on his feet and he can play in three different positions in attack. I plan to use him as a centre forward and out wide.
"He is a player who knows how to be decisive."
The 48-year-old then warned the fans not to get carried away by Kalou's signing and insisted that it may take some time for the 26-year-old to adapt to the team.
"We must not expect him to win every match for us right away," Garcia said. "There is an adjustment period for everyone, including for Kalou.
"Even if he comes from Chelsea, who are the European champions, we must be patient with him, who will have to work hard to get used to playing with his new team-mates."