Sir Gilbert is the Alpha of the Tigers. He is a polite and regal warrior.
Sir Gilbert is presented as a large orange tiger with whisker markings, flecks beneath his green eyes, and a beard separated into three braids. His attire is a red cape with a blue cloth sash fastened around his right arm with a medal of merit. The medal of merit is striped blue and yellow and the metal part of the medal is in the form of a blue cross. He also wears two rings, one with a ruby and one without. Around his neck is a plated armlet with a dark purple stone embedded in it. He also wears silvery metal cuffs on all four of his legs.
- He is named after Gilbert H. Grosvenor, the editor of National Geographic from 1970 to 1980 and creator of National Geographic Kids.
- The meaning of Gilbert is a combination of "pledge" and "bright" or "famous" with its origins coming from France.
- The Sir Gilbert’s Alpha Set and Sir Gilbert’s Pack Hideout is based on him.