Jilly first appears in the second episode of Miracle Day where she offers the controversial Oswald Danes (Bill Pullman), a recently released convicted child murderer and paedophile, representation.

[1] Danes agrees to be represented by her after being assaulted by vigilante police officers; with him assured as a client Jilly sets out to sell his celebrity status in addition to the public image of drug company Phicorp and "Miracle Day" itself.

Kitzinger also approaches the respected Washington DC surgeon Vera Juarez (Arlene Tur), but she allies herself with Torchwood—a group of renegades composed of two former alien-hunters and two former CIA agents—and distracts Jilly from an infiltration by Gwen Cooper (Eve Myles).

[2] In spite of her professional remit Jilly expresses disgust at Oswald in "Escape to L.A." when his public persona is eclipsed by Ellis Hartley Monroe (Mare Winningham), stating that she cannot look at his hands after the crime he has committed.

[5] At the climax of "The Gathering" she meets The Mother (Frances Fisher), the Shanghai representative of the Families, who introduces her to the Blessing, an antipodal geological formation which is said to show an individual the contents of their soul.

[7] Lauren Ambrose's casting was announced on 13 January 2011, with her character Jilly Kitzinger initially being billed as "a sweet-talking PR genius with a heart of stone who's just cornered the most important client of her career ... and maybe of all time".

When asked about this scene, Espenson commented that she felt this sequence gave insight into Jilly's "self-delusion" and "the ego of someone who can look into the void and walk out of it with confidence", though added the caveat that "I think the line is meant to hang there, unexplained and fantastically question-raising.

"[20] In the final episode of the fourth series, Jilly's own political views are demonstrated as she launches a morally nihilistic attack on the hypocrisies of modern society; in light of this rant Martin describes her as "the only woman who can make a Guardianista flirt with the right wing through lipstick and compassion alone.

Rob Owen writing for the Cape Cod Times described her as "a smiling shark... played with scheming glee"[22] whilst Kevin Fitzpatrick, of UGO Networks labelled Kitzinger as "our favorite fiery redhead".

[25] Dan Martin, weighing up the first eight episodes for The Guardian felt that the character was one of the highlights of the series stating that "Lauren Ambrose's daffy, deliciously amoral Jilly Kitzinger owns every scene she's in.

[29] In a retrospective of the successes and failures of the fourth series, Digital Spy's Morgan Jeffrey notes that Lauren Ambrose was "superb" stating that "in the early episodes of Miracle Day especially, she brought a sense of fun to proceedings that was absolutely vital.