Darren Ritter is a sneakily important character within Chicago Fire. He rarely takes center stage, but he is a crucial piece of firehouse morale. He's always on hand to provide support to his peers, and to ensure that things are running smoothly. Well, as smoothly as they can.
It's difficult to imagine Firehouse 51 without Ritter, which is why the original plan for the character is so bizarre to consider. During a recent profile with Chicago Sun-Times, the actor who plays Ritter, Daniel Kyri, recalled that he was only supposed to be on Chicago Fire for a handful of episodes.
Daniel Kyri helped flesh out the Ritter character

"My character was only going to be around for a few episodes, so I don’t think there was a lot of thought put into who guy was," Kyri explained. The actor impressed Chicago Fire producers and writers, however, and he kept getting worked into the show. An episode here and there, and then suddenly, 36 appearances as Ritter before he was promoted to series regular.
Kyri, who identifies as queer and grew up in Chicago, told the outlet that he worked with the Fire writers to give his character more dimension. It was a process, but one the actor thoroughly enjoyed, as he got a chance to create the sort of character he never thought he'd see on television when he was younger.
"What I love about my character is, he exists," the actor explained. "Darren Ritter is a possibility. Something I would not have been able to imagine when I was younger and coming out and dealing with what I was dealing with. I do my job, and don’t really worry about what is outside my purview."
Kyri considers playing Ritter an "honor"

Kyri, who had a brief role in Chicago Med before being cast as Ritter, also takes pride in the fact that he's been able to develop the character over a period of several years. He debuted in 2018, and has since appeared in 127 episodes (in addition to franchise crossovers).
"It holds a place of honor in my life," he told NBC in 2021. "And I don’t think that that will ever end for as long as I am blessed and able to breathe into this role." Kyri's performance has had a real world impact on his native Windy City, as evidenced by the fact that actor was the guest of honor at the Evening Ritual for St. Regis Chicago's 2nd Annual 12 Days of Sabrage. The event was held back in December, and provided warm clothing to those in need.