Why did Derrick Gibson leave Chicago Fire? The rookie firefighter left Firehouse

51 to focus on his mental heath issues, which first came to light during Episode 5.

During the episode, titled “On the Hook,” viewers learned about Gibson’s past

and how he was responsible for the death of a boxing opponent. He also confessed to Sam Carver (Jake Lockett), who he had grown close with, that after accidentally killing the man, he suffered a nervous breakdown and spent some time in a psychiatric unit. He eventually became a firefighter to block out the trauma he had experienced but never fully healed from.

Gibson’s mental health took a turn for the worse when he met a high school basketball player who accidentally injured his opponent, sending him to the hospital. Gibson was absent from a few shifts and when he returned, he displayed erratic behavior and even snapped at new paramedic Jared Lennox (Wesam Keesh) in front of everyone. Carver realized that his friend was abusing painkillers and confronted him about it, which caused an angry Gibson to slam his fist into a locker and injure his hand.

Following a trail of blood, Stella found Gibson having a panic attack and crying. “I thought I pulled it together,” Gibson told her. “I need to get out. I need to go.” With that, Gibson left Firehouse 51 to work on himself and get help for his drug problem.

Fans were sad to see the newcomer go so quickly, expressing their frustrations on social media. “So Gibson is gone? After like 5 episodes? He just joined the team. I’m so confused,” one fan wrote on X (formerly Twitter). Another fan wrote: “I was excited for Gibson, can’t believe I waited two weeks for nothing.”