Detective Lieutenant Chin Ho Kelly was a former highly decorated HPD cop before being wrongly accused of corruption which resulted in his career and reputation being tarnished.
For a short time, after Governor Pat Jameson's murder and Hawaii Five-0 being disbanded, Chin temporarily joined the Honolulu Police Department but after Steve was cleared, Hawaii Five-0 was reopened and Chin officially rejoined the team.
Born and raised in Hawaii, Chin lived a relatively normal life and during his time in high school, befriended teenage Steve McGarrett.
At some point, in his later adult years, Chin joined the Honolulu Police Department but his career was ultimately left in tatters as he took the fall for his uncle, Keako who had stolen money as Keako's wife and Kono and Chin's aunt, Mele was gravely ill and needed a kidney.
Not wanting his uncle to be shamed, Chin took the fall with many of his former officers regarding Chin as a thief.
After resigning from the HPD, Chin became a security guard with the fallout prompting him to leave his fiance, Dr. Malia Waincroft for protection.
Hawaii Five-0 Season 1
In the Pilot (episode), Chin was reunited with Steve and instantly agreed to join the unnamed Task Force, Chin's technological skills and knowledge of Hawaii in general giving the team a huge advantage.
Hawaii Five-0 Season 2
In Season Two, Chin proposed to his former fiancee, Dr. Malia Waincroft, and the two were later married in a beach ceremony, in the company of their friends and family.
He and Detective Sergeant Danny Williams (2010) join forces with NCIS Special Agent G. Callen and Special Agent Sam Hanna to stop a smallpox outbreak from happening during Pa Make Loa (episode) with both teams heading to Los Angeles to stop a worldwide pandemic from occurring in the concluding episode, Touch of Death (episode).
In the finale, he was forced to choose between rescuing his wife or cousin.
Hawaii Five-0 Season 3
In the premier, Malia died from her wounds, leaving Chin devastated although he later avenges her death while the team is later seen at her funeral (3.02). In the finale, he called Leilani out for a date.
Hawaii Five-0 Season 4
Hawaii Five-0 Season 5
In an alternate reality seen in Ina Paha (episode), as a result of the Hawaii Five-0 Task Force not being created, the Chin of that reality is presumably still highly respected and admired as a Detective.
As such, he has been promoted to Captain and also maintains a high position in the Honolulu Police Department.
Despite the accusations against him, Chin is an honest cop through and through although Chin has expressed some hurt at the fact that many of his former HPD colleagues don't trust him at times.
Chin is also greatly loyalty towards his family, having unknowingly sacrificed his own career for the sake of protecting his uncle from the fallout.
Chin is very protective of his cousin, Kono.
Like the respect of his H50 colleagues, Chin has a strong loyalty towards Steve with Chin stating that he has found a home with H50, suggesting he is happy with his job as a H50 member and that he does not wish to return to the HPD.
Chin is a slim man of Asian with long or short black curly hair and brown eyes.
Like the other members, Chin is often seen wearing the official H50 armor uniform whenever the team are in the field, pursing a dangerous suspect with Chin's vest holding additional shells which Chin will use in the event that he needs to reload his shotgun.
The third-in-command of the H50 Task Force second to Steve and Danny, Chin is exceptionally skilled in weaponry and technology, his skills a close second to Steve's.
Hand to Hand Combat
Chin is skilled in hand-to-hand combat and can easily hold his own.
Chin is skilled at using the technology that the H50 team have at their disposal. Chin is always seen with a piece of technology on him and is even capable of retrieving off a damaged phone or a SD card.
Given his experience as a cop, Chin can get into the criminal's mind and even accurately predict their next move.
Chin is skilled at interrogating.
Like the members of H50, Chin is an expert in weaponry and is seen usually wielding a SIG-Sauer P229R although he has been seen wielding a Benelli M1 Super 90 (Short Barrel)