[1] Her father, Des FitzGerald, an Irish American, is the former CEO of the ContiSea unit of the multinational corporation ContiGroup and the founder of Ducktrap River Fish Farm Inc.[2][3] Her mother, Pam Allen, is the author of Knitting for Dummies and the founder of the yarn company Quince & Co.[1][4] FitzGerald first developed an interest in acting as a child and performed in many community theatre and school productions.

[9] FitzGerald has appeared in Love Simple, It's Complicated, Gossip Girl, Whit Stillman's Damsels in Distress,[10] Blue Bloods, UnREAL and Newlyweds.

[12] Ben Brantley of The New York Times said of her performance: "All legs, eyes and cheekbones, with a face that seems made for cinematic close-ups, she’s a hypnotic pleasure to look at."

"[16] In 2015, she appeared in the indie comedy Adult Beginners from director Ross Katz as Kat, the girlfriend of Jake (Nick Kroll) who dumps him after his tech startup fails and he moves back to his family home.

[17] In June 2017, FitzGerald joined the cast of Robert Krzykowski's film The Man Who Killed Hitler and Then the Bigfoot, co-starring with Sam Elliott and Aidan Turner.