Like his good friend and fellow NCIS Special Agent Leroy Jethro Gibbs who runs the Major Case Response Team in Washington D.C, Callen is the also the lead Agent of the Office of Special Projects with his partner being former Navy SEAL, Sam Hanna.
Born in Romania to an unnamed father and Clara Callen, a CIA agent, young G. Callen lived a relatively normal life up until the age of six or seven.
The Comescu family who Callen's grandfather and possibly Clara's father had killed many members of later retaliated by killing Callen's grandparents before their daughter, Clara escape to the United States. Unfortunately, the Comescus still held a strong, undying grudge against the Callens and an assassin working for the family later killed Clara while another man distracted young Callen by giving him a toy solider.
At some point, young G. Callen and his sister, Amy were brought to the United States with both children being placed in foster homes. Amy died when she was very young while Callen grew up as part of the foster system.
Upon turning eighteen, Callen presumably joined the Army while working for the CIA in his later years. He then joined NCIS where he had assignments which had him working with Gibbs with the tasks bringing both men to Serbia and Russia with Gibbs saving Callen's life on both occasions in the two countries.
At some point, Callen was reassigned to the Office of Special Projects where he remains to this day.
NCIS Season 6
However, at the end of Legend Part 2 (episode), Callen was wounded in a drive-by shooting that Sam also happened to be witness and in the next episode, Semper Fidelis (episode), was described as being in critical condition.
NCIS: Los Angeles Season 1
Four months later Callen returned to his duties where it was later revealed that a former CIA operative Ethan Stanhope arranged the assassination attempt. Stanhope desired to eliminate all persons with knowledge of Operation Cossack a joint NCIS/CIA operation in Russia that failed when it was compromised by Stanhope. Stanhope's goal was to conceal his treasonous actions and prevent any adverse disclosures that would have harmed his business ventures.
Relationships with Colleagues
Leroy Jethro Gibbs
While on a mission in Serbia, Gibbs saved Callen's life. Gibbs also asserted that he saved Callen's life in Russia as well, which Callen denies. Callen has an intimate knowledge of Gibbs' past since he is aware of Gibbs's boat building hobby, as well as being aware of his three failed marriages. It is interesting that Gibbs in episode Legend Part 1 (episode) told Callen that he had been married four times, a fact Gibbs tends to keep close to the vest. Callen is one of five people who call Gibbs "Jethro." He gives McGee a sniper's magazine to use for conversation with Gibbs on their return flight to D.C., saying it worked for him. Callen by his own admission considers Gibbs family.
Callen also seems particularly close with his current partner, Sam Hanna. At least once in most episodes, Hanna displays mother-hen-like concern for Callen (often directed at risks he takes or his neglecting his own needs). When reflecting on a previous experience as a SEAL, he confessed to Callen "I can't lose another partner." Callen also seems to know more about Hanna's personal life than the others, including the fact that Hanna has two mentioned children.
- Callen is played by Chris O'Donnell who viewers may recognize from his role as Robin in "Batman and Robin" and "Batman Forever".
- In the first two seasons of NCIS: Los Angeles, Callen and his colleagues with the exception of Detective Marty Deeks carried a SIG-Sauer P228, the current weapon of choice for their Washington D.C counterparts, the Major Case Response Team led by Leroy Jethro Gibbs. At the beginning of Season 3, however, they switched to the new model SIG-Sauer P229 with the redesigned slide and new grips which they have continued to carry to this day.
- With the exception of JAG, Callen is the only NCIS: Los Angeles character along with Sam Hanna and Kensi Blye to have appeared on NCIS and Hawaii Five-0.
- NCIS: (6 season; 3 episodes; First appearance)
- NCIS: Los Angeles (See G. Callen on the NCIS: Los Angeles Database for more details)
- Hawaii Five-0: Episode:Pa Make Loa (Hawaii Five-0)