Mr. Chiang was Nathan Bates' second-in-command, replacing Bates' previous right hand Rollor. It is unknown what happened to Rollor but it can be implied that Mr. Chiang killed Rollor himself.
Chiang's first act as chief of security is the capture of Kyle Bates, who was immediately taken to see his father. Bates and Chiang discovered information regarding an 18 year old woman traveling with Kyle, after Kyle is caught raiding a Science Frontiers warehouse. Nathan Bates has Chiang show Kyle discipline, which he does by beating him severely until he is distracted by Elizabeth Maxwell, giving Kyle a chance to escape. Mr. Chiang is convinced Julie Parrish is the leader of the resistance but Nathan forced Mr. Chiang to find proof; Chiang then breaks into her home and grabs a disk with important information involving Science Frontiers' shipping routes, however Robin Maxwell (dressed as a cleaning lady) comes in and takes the disk.
After this Chiang is embarrassed as Nathan gets slapped by Julie; finally when it is Christmas time, Chiang is able to prove Julie is the traitor: when a spy of Bates catches him being chummy with Mike Donovan and Ham Tyler, Chiang puts together a task force to destroy Club Creole. Chiang then assisted Nathan in confirming that indeed that the Visitors had captured his son Kyle, and also helped Nathan Bates set up a prisoner exchange where a converted Ham Tyler would kill Mike Donovan. However, Elizabeth interrupts and accidentally causes the bullet to hit Nathan instead.
Mr. Chiang gets Nathan back to Science Frontiers, where he keeps Nathan alive, although in a coma. Chiang is hesitant to work with the Visitors again due to what happened last time, however he was convinced by Charles who used a computer program to simulate Bates on television screens so Chiang could rule Los Angeles with Bates as figurehead. However, when Bates wakes up from the coma, Chiang realizes that he is in too deep and that Nathan would not be happy with Chiang's actions; when Charles suggests killing Nathan, Chiang thinks this is a good idea. Chiang hunted down Nathan after Kyle was caught trying to escape with him - Chiang shot Nathan dead, but Kyle escaped not too long afterwards. Kyle tracked Chiang down to Nathan's office and killed Chiang in revenge for Nathan's death.