Many think that Mikey is a bully just because of his height, but, as once described by T.J. Detweiler, "he wouldn't hurt a fly". There is a hidden agenda about him, and that is his love for "Bonky the Dinosaur". Bonky is a dinosaur in ways similar to Barney the dinosaur and is loved by the kindergarteners. In the episode Bonky Fever it is shown that and the rest of the gang try to stop it. In his birthday party, once the gang thinks he has stopped the Bonky nonsense they all see a party full of Bonky things and toys. But thanks to the gang he founds out it is his mother in a Bonky costume and does eventually stop showing his love for Bonky.
Mikey does have another hidden agenda which is his singing voice. He believes he cannot sing anywhere apart from the bathroom. Until Principal Prickly and Miss Finster get him a private music teacher who helps him feel confident in singing other places. She trains him for the Spring Fling, which he would succeed in and do everyone proud.
T.J. is good friends with Mikey. In "The Break-up", T.J. says he "appreciates his insane spiritual gifts". However he is sometimes embarrassed by Mikey's behavior. In "Tucked In Mikey", after Mikey read a poem inspired by Menlo, T.J. claimed "for once, it didn't embarrass me". He also was a little embarrassed at Mikey's comment that the 5th and 6th grader's club was a "rainbow hug of togetherness". But, T.J. respects Mikey despite his behavior, as seen in the end of "Rumor Mill".
Although the status of their friendship is not seen very much, it's obvious the Gretchen and Mikey are good friends.
Mikey looks up to Vince, which is the focus of the episode "Copycat Kid". Mikey wishes he could be "cool" like Vince and be sporty (and was quite capable of shooting baskets in the episode), until Vince copies him. In the end Mikey realizes the value of himself as an individual. The two remain good friends afterward.
Mikey and Spinelli are polar opposites. Mikey is large and peaceful, while Spinelli is small and more violent. Mikey's sincerity and calm demeanor sometimes get in the way with Spinelli's attitude ("Gus's Last Stand", "Rumor Mill") The two share a rare moment of friendship in the episode "Dance Lessons", where Spinelli puts aside her tough attitude for Mikey's sake. She also was ready to defend Mikey when Randall made jokes about him in "Stand Up Randall", which Mikey appreciated but said it was not necessary.
Mikey is better friends with Gus than any of the other members. The two are often seen taking the same side on things (Recess: Taking the Fifth Grade, "The Candidates"). They have offended each other occasionally ( "The Break-up", "Germ Warfare") but were quick to forgive one another.
- His singing voice is that of the late Robert Goulet.
- Mikey is the only member of the main six whose birthday has been celebrated in an episode, "Bonkey Fever". Gretchen mentions her birthday party in "The Girl Was Trouble", however, it was only a flashback.
- Mikey is based on Paul Germain's friend back in elementary school.
- According to "To Finster with Love", Mikey weighs 110 pounds.
- Mikey has had the second most episodes focused on him out of the entire cast.