Dr. Mitch Ripley’s childhood friend Robert “Sully” Sullivan reappears in Seasons 9–11 of Chicago Med.
Sully, played by Daniel Dorr, battled terminal cancer and died after complications following treatment.
His death led to emotional scenes: a prison visit, Ripley’s near-breakdown, and a Wrigley Field ashes memorial.
Sully’s storyline pushed Ripley toward new relationships and dramatic choices at Gaffney.

Who was Sully on Chicago Med?

If you’ve searched “who was Sully on Chicago Med,” here’s a concise answer: Sully is Robert “Sully” Sullivan, a childhood friend of Dr. Mitch Ripley. Portrayed by Daniel Dorr, Sully first reconnects with Ripley in Season 9 and becomes central to several emotional storylines that follow.

Sully’s relationship with Ripley

Ripley and Sully grew up together in a rough neighborhood. As adults, Ripley turned his life around to become a doctor, while Sully struggled with personal demons. Despite that, the two remained close; Sully deeply cared for Ripley and his longtime partner Lynne.

Terminal cancer and the tragic decline

Sully’s arc takes a heartbreaking turn when he’s diagnosed with terminal cancer. He and Lynne decide to fight the disease, and viewers watch Sully undergo chemotherapy at Gaffney. His condition briefly shows promise, but complications—including a dangerous blood clot—cause a sudden decline.

Before his death, Sully also tries to protect Ripley from legal trouble. After assaulting a patient who he believed was harming Ripley, Sully is arrested. The incident deepens the drama: Ripley nearly takes the blame, but Sully confesses to avoid stealing Ripley’s remaining time with his family.

How did Sully die?

Sully dies off-screen after a brutal cancer battle that culminates with a lethal blood clot. His death is a turning point for Ripley—both emotionally and narratively—and the show revisits their bond in later episodes through memory-driven scenes and Ripley’s personal growth.

Sully’s memorial: Wrigley Field break-in

Season 11 features a memorable tribute. On the one-year anniversary of Sully’s death, Ripley and Lynne secretly enter Wrigley Field to spread his ashes—honoring Sully’s love of the Cubs. The moment blends grief and celebration, and it nudges Ripley toward living more boldly.

Aftermath: Ripley’s choices

The loss of Sully influences Ripley’s relationships at Gaffney, including a surprising romantic spark with E.D. Chief Caitlin Lenox (Sarah Ramos). Lynne encourages Ripley to take risks, crediting Sully as the “best bad idea” she ever had—and pushing Ripley to act on his feelings.

Where to watch

Chicago Med airs Wednesdays at 8/7c on NBC and streams the next day on Peacock.

For fans asking “who was Sully on Chicago Med,” his storyline remains one of the series’ more emotional threads—built around friendship, illness, and the messy aftermath of loss.

Image Referance: https://www.nbc.com/nbc-insider/who-is-sully-what-happened-chicago-med