Anastasia Arkadievna Kolcheck is the only child of Arkady Kolcheck. She was born in Moscow, but moved to Illinois at a very young age, speaking English in school and Russian at home.
After high school, Anna cut off the contact to her father and moved to Chicago, where she eventually joined the local police department. That was the beginning of her long, successful but somewhat chaotic career in law enforcement.
The next time Anna saw Arkady, she was kidnapped by enemies of his, who used her to force his hand. She was rescued by the NCIS, with her father's assistance. That was the day she first met G. Callen.
Throughout the following years, she occasionally worked with Callen's team in Los Angeles. She temporarily replaced Kensi Blye in 2016, because the other woman was injured and unable to go into the field. Around that time, Callen and Anna began their messy on-again-off-again relationship.