The Senior Chief was seen eating donuts in Dot's Diner when the CPU Chief rushed in and told him that there was another abduction in Mainframe, this time it was Al's Waiter. Bob hadn't heard about the abductions and demanded to know what was going on. The Senior Chief informed Bob that they had received reports of missing sprites on Level 31. Enzo Matrix, AndrAIa, and their teacher, Miss Brodie, rushed in to tell Bob that Dot Matrix had gone missing as well.
Bob asked Mouse to take Enzo and AndrAIa to the Principal Office while he went to Level 31. Mouse asked Miss Brodie if she would take the kids to the Principal Office for her, and said that the Senior Chief and Chief would probably escort her there. (Trust No One)
The Senior Chief helped Phong operate the War Room during the Web War. They successfully organized the CPU Fleet and the ABC Attack Fleet in defending Mainframe from the Web long enough for a team to activate the Hardware and close the Web Portal. The Senior Chief watched in horror when Megabyte and Hexadecimal contacted the Principal Office and ordered their unconditional surrender. (Web World Wars)
- The Senior Chief was only ever referred to as Chief in ReBoot. However, the CPU Chief was also referred to as Chief, but was obviously lower ranked than the Senior Chief. For this reason it is reasoned that the higher ranked individual must be a Senior Chief.
- The Senior Chief only appeared in two episodes, both in the second season.