As a child, Moonwatcher spent a great deal of time being taught by his father, who had planned for Moonwatcher to take his place as Guardian when he got older. When Steppenwolf and Christopheles decided more than one Guardian would be necessary to protect the Floating Island from internal and external threats, Steppenwolf brought Moonwatcher to Haven for the first time. Following this Moonwatcher worked as a team with his father, trading shifts and duties between looking after the Floating Island and its Chaos Emerald and ascertaining the threats posed on Mobius' surface. (KtE: #25)
During Moonwatcher's tenure as Guardian he defeated the Dark Legion during one of their many breakouts of the Twilight Zone, sending them back to their imprisonment. Additionally, he helped introduce a number of different Mobian species to the Floating Island, notably the Chameleons of Rainbow Valley. Presumably unbeknownst to him, this group-in later generations if not beginning in his time-would come to include Shinobi Clan ninja assigned to observe the Brotherhood in secret. (KtE: #18, SU: #16, CSE)
When Moonwatcher became an adult, he followed in his father's footsteps, training his son Harlan to become a Guardian from a young age. By the time his grandson Rembrandt came of age there were four active Guardians, which Rembrandt christened "the Brotherhood". After the death of Rembrandt's son Aaron, Moonwatcher and Harlan felt that Rembrandt's new method of training Jordan was wrong and that they should all participate in his training, though Steppenwolf pointed out Jordan should learn slowly before his responsibilities were increased. (KtE: #18, #25)
Dying at some point of either old age or other causes, he appeared at Knuckles the Echidna's funeral along with the other deceased Guardians, and mistook Chao messengers from Aurora as arriving to guide his father to the Chaos Force. (StH: #121)
Unlike his father, who was calm and reserved, Moonwatcher was an energetic and and more open. He was willing to work with his father when he appointed him to work along side him as a guardian. He appears to be one of the more optimistic guardians, and seemed a bit hasty, this is shown when he instantly assumed that the Aurora's Chao messengers had arrived for Steppenwolf. (KtE: #25, StH: #121)
- Moonwatcher is one of the few members of the Brotherhood who wears a full-out uniform.
A red echidna, Moonwatcher's design is very similar to that of Star Trek: The Next Generation character Geordi La Forge. His longsleeve, two-toned shirt bears a triangular emblem on the upper left and his eyes are covered by a green visor. Like most Guardians, he wears two-fingered, spiked gloves. In some early depictions, his muzzle was notably darker than average.