[2] Mike was designed by series creators Matt and Ross Duffer to be a prototypical 80s main character who is loyal and energetic while also innocent due to his young age.

[3] At the beginning of the series, Mike is playing Dungeons & Dragons with his best friends, Dustin Henderson (Gaten Matarazzo), Lucas Sinclair (Caleb McLaughlin), and Will Byers (Noah Schnapp) on November 6, 1983.

[4] The next day, Mike, Dustin, and Lucas find a girl with a shaved head named Eleven (Millie Bobby Brown).

Later, Will's corpse is apparently found in a local quarry, but the boys are convinced that Will is alive and in a parallel dimension, which they call the “Upside Down”.

Troy grabs Dustin and threatens to maim him if Mike doesn't jump off a nearby cliff.

To the bullies’ surprise and Dustin’s horror, Mike jumps; however, he is saved and pulled to safety by an unseen force, which is revealed to be Eleven.

After injuring the bullies and forcing them to flee, Eleven apologizes to Mike and Dustin, who reassure her and reaffirm their friendship.

The group eventually build a makeshift sensory deprivation tank at Hawkins Middle School to allow Eleven to amplify her powers to find Will.

Dustin and Lucas become infatuated with new student Maxine "Max" Mayfield (Sadie Sink) and attempt to get her to join their group.

Mike and Will witness Hawkins Lab agents torching parts of the Upside-Down from underground tunnels, causing Will to begin screaming and convulsing on the ground.

The group attempt to figure out how to get rid of the Mind Flayer for good and travel to Eleven and Hopper's house where Mike blurts out that he loves her and cannot lose her again.

Mike, Eleven, and Max are separated from everybody else; they manage to hide before Lucas, Will, Nancy, and Jonathan distract the Mind Flayer.

He knocks Mike and Max unconscious, and brings Eleven to the center of the mall, where the Mind Flayer has returned.

Mike is now part of Hellfire, a Dungeons and Dragons club at his school, alongside Dustin and Lucas, which is run by Eddie Munson.

"[9] Liz Shannon Miller, Steve Greene, Hanh Nguyen, Ben Travers of IndieWire said that "his...tenacity to keep ...is a credit to his character.