On this season of Chicago Fire, when Herrmann heads out for a vacation, Casey (Jesse Spencer) is not thrilled with his replacement — Lt. Greg Grainger (Jon-Michael Ecker). When Grainger made his first appearance on the show, he flirted with Sylvie (Kara Killmer), who continues to flirt back.
In real life, actor Jon-Michael Ecker (Queen of the South, Narcos, Firefly Lane) who plays Grainger is in a relationship with actress Laura James, who plays lawyer Molly Hicks, daughter of LAPD S.W.A.T. Commander Robert Hicks, on S.W.A.T.
Chicago Fire airs Wednesdays at 9 pm on NBC, right after Chicago Med at 8 pm and right before Chicago P.D. at 10 pm.