Sakura was assigned to Kakashi's team after graduating from the Ninja Academy. She was almost dropped from the program all together but passed when she fed some of her food to Naruto despite being told not to. During a mission to the Land of Waves, Sakura protected their escort during an attack and Kakashi told her that she did a great job. When he taught his team how to walk up trees, Sakura mastered the technique right away and Kakashi was impressed.
When the time came for the Chunin Exams, Kakashi recommended Sakura along with the rest of her team. During the third round, the village was attacked and Sakura was one of the few who escaped the effects of a Genjutsu. Kakashi trusted her to wake up Naruto and Shikamaru and go on a mission to chase Sasuke and Gaara. He then summoned his dog Pakkun to help them.
Naruto and Sasuke eventually fought on the rooftop and Sakura was caught in the middle. Luckily, Kakashi arrived at the last second to stop the fight. Sakura started crying after Naruto yelled at her so Kakashi smiled and promised her that things would be okay. However, Sasuke then left the village to go train with Orochimaru despite the fact that Kakashi lectured him about his behavior.
Sakura barely saw Kakashi over the next two years while she was training with Tsunade. However, once Naruto returned, they were administered another bell test and succeeded. Kakashi and Sakura were then registered on a new team along with Naruto. They were later placed on a mission to rescue Gaara and worked together to try and save him. However, they were separated during the fight against Deidara and Sasori.
Kakashi later witnessed Sakura confessing to Naruto and prevented Yamato from interrupting. Sakura later confronted Sasuke and he attempted to kill her from behind. Luckily, Kakashi arrived to save her at the last second. He was furious with Sasuke for trying to kill her. Kakashi ordered Sakura to tend to Karin but she eventually got back into the battle because she wanted to help him.
KakaSaku is rather popular in the Naruto fandom. This is mainly due to the fact that they are on the same team and interact a lot. A lot of fans also feel that their personalities compliment each other very well. Some also point out the fact that Sakura is similar to Kakashi's former teammate, Rin. KakaSaku tends to rival the SasuSaku, NaruSaku and KakaRin pairings.