G. Callen (born: Grisha Alekandrovich Nikolaev) is a fictional character in the show NCIS: Los Angeles portrayed by Chris O'Donnell. He is an NCIS Special Agent in Charge, and the senior agent assigned to the Office of Special Projects. O'Donnell made his first appearance during NCIS ' sixth season episode "Legend (Part 1) ''.
what does the g stand for in agent g callen
Grisha