Who Was Dr. Jeff Clarke on Chicago Fire and Chicago Med?

Clarke made his first One Chicago appearance in Chicago Fire Season 2, Episode 1 ("A Problem House"), and stayed on for several seasons of the NBC nail-biter. He was on the relief team for Firehouse 33 before making his way to Firehouse 51 and aboard Squad 3 with Kelly Severide (Taylor Kinney).

Prior to his turn at Firehouse 51, he had been a Marine stationed in Iraq, and his experience there shaping his ability to swiftly respond to a crisis whether at the firehouse or in the Emergency Department. 

RELATED: Where to Watch Chicago Med, Chicago Fire, and Chicago P.D.

Clarke arrived at Firehouse 51 around the same time CFD Financial Director Gail McLeod (Michelle Forbes) set her sights on the station to cut costs around the department.

In Clarke's debut episode, McLeod asked him to be a makeshift mole for her to collect information on 51, but he didn't have any interest. Regardless, in Season 2, Episode 2 ("Prove It") — after it was clear McLeod had been spying — the 51 firefighters became suspicious of Clarke due to his quiet demeanor and reserved stance.

Clarke cleared up the snitch rumors in Season 2, Episode 4 ("A Nuisance Call") when it was revealed a Firehouse 33 firefighter had ratted to McLeod. 

Clarke had a complicated romantic history prior to his stint on Chicago Fire that reared its head in Season 2, Episode 7 ("No Regrets"), when his ex-wife, Lisa (Victoria Blade), paid a visit to the station in hopes of rekindling their relationship.

Lisa, it turned out, had left the marriage while her husband had been deployed and, though the two argued at first, Clarke decided he was willing to try reconnect with his ex after witnessing the death of a fellow veteran while on a call.

Clarke, however, discovered that Lisa had been seeing another man, Brian Hayes (Michael Huftile), during his deployment and after their separation and the two seemed to still have a connection. He confided in Christopher Herrmann (David Eigenberg) that he worried about getting mixed messages from Lisa and unsure how to proceed with the relationship.

But as Clarke, Severide, and Herrmann were sharing a drink at Molly's in Season 2, Episode 10 ("Not Like This"), Hayes showed up, demanding money from Clarke that he said Lisa owed him, and hurling vile insults her way. Clarke blew up at Hayes, going as far as threatening to kill him if he ever saw him again. This comment was decidedly bad for Clarke: Hayes was murdered later that night, and his threats catapulted Clarke to the top of CPD's suspect list. 

Clarke was released on bail in the following episode ("Shoved In My Face") but was less than cooperative with CPD's investigation. After the cops went through Hayes' phone, they discovered there wasn't ever an unpaid debt, and that Lisa had indeed welcomed Hayes back into her life willingly after he'd cheated on her.

The revelation — and his ex's unwillingness to deny it — was enough for Clarke to step away from his relationship with Lisa, whom he had to that point been trying to protect with his silence. Clarke provided the police with an air-tight alibi, cleared his name, and returned to 51 in Season 2, Episode 10 ("Out With a Bang"). 

In the Season 2 finale of Chicago Fire ("A Heavy Weight"), Clarke earned a promotion to lieutenant, prompting his transfer to Firehouse 25. Clarke thrived off-screen as a commander but fans learned in Season 5, Episode 8 ("One Hundred") — which originally aired in December 2016 —that he'd suffered a nasty back injury in the line of duty after leaving 51, ending his career as a firefighter.

RELATED: Why These One Chicago Stars are Leaving Their Shows

The injury, Clarke told Severide in the episode, served as his inspiration to enrolling in medical school in Chicago and pursue a career in medicine. Clarke's final Chicago Fire appearance — as a medical student — was in Season 5, Episode 10 ("The People We Meet"). 

However, before his return to Chicago Fire, Clarke made his first Chicago Med appearance in Season 1, Episode 18 ("Timing") — which first aired in May 2016 — alongside a group of fellow medical students. It was then revealed that Clarke was an old friend of Natalie Manning's (Torrey DeVitto) and that he had been her late husband's best friend. 

In the Season 2 premiere of Chicago Med ("Soul Care") — which aired in September 2016 — Clarke started his rotation in Gaffney's Emergency Department and set out to get more involved with cases, but didn't gel well with Dr. Will Halstead (Nick Gehlfuss). Clarke later performed a procedure on a patent without the supervision of attending, a big no-no.

Halstead and Clarke got into a huge argument about the error, but the argument seemed more connected to their shared attraction to Manning rather than Clarke's actions — especially since Halstead didn't write Clarke up for the incident.

Manning and Clarke's past laid the foundation for a love connection, and the two were seen heading home together in "Soul Care" after sharing a drink at Molly's.

As the two got deeper into a relationship, they unsuccessfully attempted to keep it hidden from their Med colleagues. In Season 2, Episode 4 ("Brother's Keeper"), the pair drove to work together but left the car separately in order to keep up their act. But Halstead called Manning out, telling her everyone in the hospital already knew about her relationship with the medical student.

RELATED: Torrey DeVitto Reveals Why She Returned for Chicago Med's Surprising Finale

In Season 2, Episode 9 ("Uncharted Territory"), Clarke confessed to Manning that he'd told her husband he had feelings for before they deployed, which ended the men's friendship. Manning was infuriated over this revelation, and began to question their relationship

The couple broke up in Season 2, Episode 10 ("Heart Matters") after Clarke's revelation and a subsequent work-related debacle that resulted in Manning getting cautioned by a superior for dating a medical student.

Chi-Hards bid farewell to Clarke in Chicago Med Season 2, Episode 22 ("White Butterflies") after he finished his medical school rotation and he was matched with a hospital in Hawaii for a residency.

After years of grueling house fires and high-stakes medical cases, the sunny shorelines appealed to Clarke, prompting his transfer and eventual exit from the One Chicago universe.