The One Chicago franchise, encompassing Chicago Fire, Chicago P.D., and Chicago Med, has seen numerous characters depart over its more than a decade on air. However, the year 2024 brought a particularly significant wave of exits across the three series, impacting the established dynamics of Firehouse 51, the Intelligence Unit, and Gaffney Chicago Medical Center. This analysis examines these notable departures, detailing the circumstances of each character’s exit and their overall impact on the respective shows, ranked by their perceived emotional resonance with the audience.

Dr. Zola Ahmad (Chicago Med)

Dr. Zola Ahmad (Sophia Ali), a third-year emergency medicine resident at Gaffney Chicago Medical Center, was introduced in Season 9 of Chicago Med. Hired on a probationary basis under Dr. Crockett Marcel, Zola arrived with a history of dismissals from previous roles due to her impulsive medical decisions. This pattern continued on her first day, as she prematurely decompressed a patient’s neck hematoma outside an operating room and brought in a large group of refugees with suspected infectious diseases. Despite warnings, her recklessness persisted, culminating in her firing in Season 9, Episode 9, “Spin a Yard, Get Stuck in Your Own String,” after nearly endangering a living patient in a rushed effort to transport organs for a transplant. While occasionally well-intentioned, Zola’s consistent rule-breaking and high-risk experimental approaches often caused more harm than good, leading to her being one of the less mourned departures from the medical drama.

Derrick Gibson (Chicago Fire)

Derrick Gibson (Rome Flynn) joined Chicago Fire in Season 12 as a firefighter on Truck 81, replacing Blake Gallo. His backstory revealed a past as an amateur boxer who became a firefighter after accidentally killing an opponent, a trauma that also led to a medication addiction. Despite a promising character arc, Gibson’s tenure was brief, spanning only six episodes. His departure in Season 12, Episode 8, “All the Dark,” saw him leave Firehouse 51 after Lieutenant Stella Kidd discovered him experiencing a panic attack, overwhelmed by his past. Gibson recognized his need for help, stating, “I need to get out. I need to go,” and subsequently left to address his struggles with addiction and trauma. This swift exit, only a few episodes into his introduction, left viewers with limited opportunity to connect with his character or fully explore the complexities of his personal battles.

Blake Gallo (Chicago Fire)

Blake Gallo (Alberto Rosende), a firefighter on Truck 81, arrived at Chicago Fire in Season 8, filling the void left by Brian “Otis” Zvonecek’s death. His compelling backstory, involving the loss of his entire family in a childhood house fire from which he was saved by firefighters, provided a profound motivation for his career. Throughout his time, Gallo’s dynamic with paramedic Violet Mikami, from academy rivalry to a brief romance, captivated viewers. He also had relationships with Tracy Herrmann (Christopher Herrmann’s niece), Gianna Mackey, and a woman named Cara. Often portrayed as a source of comedic relief and a loyal sidekick, his narrative rarely reached the central heroic arcs of characters like Kelly Severide or Matt Casey. Gallo’s departure in the Season 12 premiere, “Barely Gone,” saw him move to Detroit to live with his aunt, his last remaining relative, continuing his firefighting career there. His exit felt somewhat rushed, and the abruptness of his relocation to another city, while logical within his family context, left his character arc feeling incomplete despite his established presence and contributions at Firehouse 51.

Sylvie Brett (Chicago Fire)

Sylvie Brett (Kara Killmer), a paramedic on Ambulance 61, became one of Chicago Fire’s most beloved and enduring characters. Introduced in Season 3 to replace the deceased Leslie Shay, Brett initially faced the challenge of living up to a fan favorite but quickly established herself as an integral and formidable member of Firehouse 51. Her personal story, including her adoption and later reconnecting with her birth mother, Julie, provided rich narrative depth, culminating in Julie’s death in Season 8. Brett’s relationship with Captain Matthew Casey blossomed into one of the series’ most cherished romances, often considered alongside “Stellaride” as a fan favorite. Her final appearance in Season 12, Episode 6, “Port in the Storm,” featured her long-awaited wedding to Casey. She then relocated to Portland, Oregon, with her daughter Julia, to join Casey and his two adopted sons, Griffin and Ben Darden (whom Casey had moved to Portland to care for in Season 10 after their mother’s imprisonment and father’s death). This emotional and fulfilling conclusion, uniting her with her love and family, provided a fitting and well-deserved send-off for a character who had grown immensely over her tenure.

Hailey Upton (Chicago P.D.)

Detective Hailey Upton (Tracy Spiridakos) marked a deeply felt departure from Chicago P.D. in 2024. Joining the Intelligence Unit in Season 4 to replace Erin Lindsay, Upton quickly evolved from a recurring character to a series regular in Season 5, earning a place as one of Sergeant Hank Voight’s most trusted and formidable detectives. Her capabilities were further highlighted after the Season 10 exit of her ex-husband, Detective Jay Halstead, allowing her to take a more central investigative role within the unit. Upton’s compelling narrative arc included a complex and often tumultuous relationship with Halstead, as well as a difficult backstory involving family abuse that shaped her resilient yet often guarded personality. Her final season saw her lead multiple significant investigations, including the critical case of Voight’s kidnapping in the Season 11 finale. This demonstrated her growth and steadfast commitment to justice, solidifying her legacy as one of Chicago P.D.’s most formidable and dedicated detectives, whose absence will undoubtedly impact the dynamic of the Intelligence Unit.

Chief Wallace Boden (Chicago Fire)

Chief Wallace Boden (Eamonn Walker) represented arguably the most profound and heartbreaking exit from the One Chicago franchise in 2024. As the Deputy District Chief for the Chicago Fire Department, Boden was among the last original series regulars on Chicago Fire, and indeed the sole original character from the entire One Chicago universe to depart in the past year. Though not always in the narrative spotlight as frequently as characters like Severide or Casey, Boden’s unwavering leadership, moral compass, and profound impact resonated deeply with both the audience and every member of Firehouse 51 throughout its history. His significance was underscored in his final full-time episode, “Never Say Goodbyes,” which depicted a collective and emotional farewell from the entire Firehouse 51 family, highlighting the immense respect and love they held for their chief. Boden’s role as the steadfast leader who anchored the squad for over a decade leaves an immense void, fundamentally altering the dynamic of the series, despite the possibility of his return in a recurring capacity in future seasons. His departure marks the end of an era for Firehouse 51, signifying a monumental shift in the leadership and heart of the series.