Joe Keery Had an Emotional Role on Chicago Fire Before Starring on Stranger Things

During his brief Chicago Fire guest arc in 2015, Keery played a young man named Emmett Bird, the half-brother of Mouch's biological daughter, conceived via sperm donation. Keery appeared in Season 3, Episode 16 ("Rag the Bull") and Season 3, Episode 17 ("Forgive You Anything").

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Keery is a bona fide Chi-Towner; he graduated from DePaul University's Theatre School and, under his musician stage moniker Djo, delivered the viral hit "End of Beginning," beloved in part thanks to its infectious bridge, "And when I'm back in Chicago, I feel it..."

Long ago, Mouch donated at a sperm bank to get some extra cash, virtually forgetting about the act for years. That is, until Season 3, Episode 16 ("Rag the Bull"), when Mouch got a call from the sperm donation bank informing him that there was a complication and he needed to visit the office ASAP. Once there, Mouch learned there was a security glitch and that the confidential files of several donors had been compromised.

The sperm bank called everyone whose donation led to a conception to disclose that their identity may have become public. Mouch was stuck on the kid detail — his DNA resulted in a child? The representative assured him that wasn't in question: Mouch was a father. It was just a matter of whether or not his biological child may reach out to him.

Mouch was pretty rattled by the news, instantly in his head after realizing he had no clue he'd been a biological father. The situation got even more interesting after Mouch received an unexpected voicemail from a young man named Emmett Bird claiming to be his son. Emmett asked to meet with Mouch at a local diner to meet each other for the first time, rendering Mouch speechless as he deleted the message. However, after talking to his wife, Trudy Platt (Amy Morton), he decided that meeting his biological kid couldn't be bad.

Mouch showed up at the diner but got cold feet after spotting Emmett waiting outside. Mouch left without saying a word, abandoning Emmett. Mouch instantly regretted this choice but didn't have much time to stew; in Season 3, Episode 17 ("Forgive You Anything"), Emmett visited Mouch at Firehouse 51 to confront him. After Mouch attempted to introduce himself as his dad, Emmett got down to business.

"No, man, you're not my father," Emmett told him.

"I apologize," Mouch said. "Birth father, I guess I should say—"

"You're not that either," Emmett snapped. "My half-sister is your birth kid. I'm a little protective, so I wanted to reach out and meet you first. Sus you out. Man, I'm glad I did. So it wasn't her left sitting in that diner like some sucker."

"Yeah," Mouch said shamefully. "I'm really sorry about that."

"Yeah, don't bother with excuses. I just came here to say that because you were too chicken to show, you'll never get a chance to meet the sweetest, coolest girl."

Mouch naturally felt pretty torn up about the exchange, knowing he made the wrong call to run away from Emmett. After touching base with Trudy, Boden (Eamonn Walker), and Herrmann (David Eigenberg) on the matter, Mouch visited Emmett at his workplace and tearfully begged for the opportunity to get to know his daughter.

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Accepting his apology, Emmett gave Mouch the contact information for his biological daughter, a young woman named Lizzie, endearingly played by Stolte's real-life daughter, Corinne Anderson. That night, Mouch and Lizzie met for the first time, sharing an emotional embrace and kick-starting the first chapter of their relationship. And it was all thanks to Keery's Emmett Bird, who helped Mouch see the light.