The 33-year-old wrapped up the victory at the Olympic Stadium with his 67th-minute effort after Vedad Ibisevic and Ondrej Duda fired the Old Lady ahead in the first half.
The triumph came as a relief for Hertha, who ended an eight-game winless streak with their first victory since March 2 [vs. Mainz 05].
Pal Dardai's side moved to 10th in the Bundesliga table with 40 points from 32 matches. They will be looking to build on Saturday's win when they take on Augsburg and Bayer Leverkusen for their last two league games of the season.
After making 97 international appearances, Kalou has not played for Cote d’Ivoire since 2017, but the former Chelsea star will turn his attention to the Elephants’ campaign at the 2019 Africa Cup of Nations.