Oobi has fair skin and no accessories other than his distinctive acrylic eyes. In the shorts, his eyes are dark brown. In the full-length episodes, his eyes are hazel.
Oobi is friendly and inquisitive. His good-natured and ever-curious demeanor is a personality that young children can easily relate to.
Oobi's favorite toy is his miniature red car, modeled after a Ford Mustang. As a hand, he is naturally talented at playing the piano and dreams of becoming a pianist when he grows up. He takes lessons from a traveling piano teacher named Inka. His closest friends are Kako, his neighbor and favorite playmate; Frieda, an older girl who is portrayed as a talking foot puppet; and Angus, his nerdy fellow piano student.
- According to an interview with the series' creator, Josh Selig, Oobi's name was chosen because of "the two O's and the relation between the eyeballs."
- Oobi and Grampu's eyes are of slightly different sizes, though they are the same color.
- Oobi is the only character featured in each segment of every half-hour episode.