While he is a very serious and stoic, by the book person he is very willing to follow Jane's investigations and he is very behind Lisbon, almost unwilling to follow anyone except Lisbon or Jane. He is also very good at dealing with Jane's collateral damage and is a first class interrogator, as he lays down all the facts and then the possible scenarios that could have played out in a sympathetic way.
When he was younger, Cho was a member of a gang called the Avon Park Playboys; his nickname in the gang was "the Iceman". After spending some time in juvenile detention, he apparently got on the straight and narrow and joined the U.S. Army where he served in Asia with the 1st Special Forces Group.
After the death of Red John at Patrick's hands and the shutdown of CBI, Cho joined the FBI after completing the Quantico training. He works alongside Supervising Agent Dennis Abbott, Agent Kim Fischer and Agent Jason Wiley.
Cho is promoted to Supervisory Special Agent in "Copper Bullet" after it is revealed that his boss, Abbott, is transferring to Washington.
- According to Van Pelt, Cho hates pineapple (The Thin Red Line).
- As seen in the episode His Red Right Hand, he avoids drinking most alcohol; in this episode everyone has drinks in memory of their colleagues who have died but while Cho raises the glass, he doesn't drink from it, but drinks water instead. In Red Scare, Cho sniffs the wine offered at the end of the episode but then sets his glass down on the table.
- Cho seems to enjoy reading as he is seen reading books in a variety of episodes.
- He used to work for a Narcotics division. (Devil's Cherry)
- According to a character list from the Pilot script, Cho was originally named "Kendall Cho", came "from twenty generations of farmers" and had a family.
- He has unexpected skills as a ladies' man which he displays in the episode Crimson Casanova.
- He is a bit superstitious as we see in the episode Red Rum.
- He is the only character, along with Teresa Lisbon and the protagonist Patrick Jane, who appeared in every single episode of the series.
- As a teen, Cho was involved in a gang called the Avon Park Playboys, in which he committed one or more crimes
- He Appears to be thought and Insensible to human emotions, the only time that he shows real emotions is in Nothing Gold Can Stay when Michelle Vega dies close to him, crying in secret.
- He is barely seen smiling but at the end of Rhapsody in Red he is seen laughing after Rigsby's wallet is stolen.