Leslie began acting professionally in high school, but her career kicked-off after she graduated a year early and moved to New York City. She landed her first major role as a potential murder victim in the 2012 film Chained, while focusing mostly on television projects. In addition to several guest starring gigs, she appeared as a series regular on Klondike, Other Space, and Shots Fired between 2014 and 2017.
Arguably Leslie's most prominent television appearance during this period was her Small Role, Big Impact turn as Trudy Walker, Juliana Crain's ill-fated sister on The Man in the High Castle. Despite being killed by the first episode, she continued to play an integral part in the series during the second and third seasons.
After leaving The Man in the High Castle for good in 2018, Leslie gained new recognition as Donna Troy, the original Wonder Girl, on the HBO Max series Titans. Leslie appeared in only two episodes of the first season, but quickly established herself as a fan favorite and was promoted to the main cast for the second season. Although she seemingly exited the series under controversial circumstances, she returned in the third season, which was partly-spoiled by the show's advertising.
- Beware the Gonzo (2010) as Amy
- Chained (2012) as Angie
- Parts Per Billion (2014) as Des
- Dirty Beautiful (2015) as Nicole
- Campus Code (2015) as Greta
- Down (2017) as Amber
- Shrimp (2018) as Sasha
- Dark Web: Cicada 3301 (2021) as Gwen
- The Unusuals (2009) as Karen Delmonte
- Law & Order (2010) as Eliza
- Law & Order: Criminal Intent (2010) as Mia Caruso
- 90210 (2010) as Parker
- No Ordinary Family (2011) as Chloe Cotten
- Rizzoli & Isles (2013) as Ms. Barlow
- Revenge (2013-2014) as Bianca
- Klondike (2014) as Sabine
- Hawaii Five-0 (2014) as Kelly Donovan
- The Man in the High Castle (2015-2018) as Trudy Walker
- Other Space (2015) as Natasha
- The Blacklist (2015) as Gwen Hollander
- Major Crimes (2015) as Mary Lowe
- Elementary (2016) as Molly Parsons
- Graves (2016-2017) as Tasha Ludwig
- Shots Fired (2017) as Sarah Ellis
- Gone (2017) as Holly Greco
- Titans (2018-present) as Donna Troy
- Big Applesauce: Born in nearby New Jersey, she's lived in the city since leaving high school.
- Camera Fiend: When not acting, she works as a photographer.
- Contralto of Danger: Possesses a husky alto voice, which serves her well as Action Girl Donna Troy.
- Dawson Casting: Although she actually was a teenager in her early roles, she continued to play teenage characters up until she was 23. Notably, she portrayed a 16-year-old on a 2014 episode of Hawaii Five-0 two years after appearing as an 18-year-old in Chained and four years after appearing as a 17-year-old on Law & Order.
- Gender-Blender Name: Conor may be unquestionably a man's name in its native Ireland and the United Kingdom, but it's found use as a female name in her home country of the United States.
- Grade Skipper: She graduated from high school as a junior.
- Ms. Fanservice / Fan Disservice: While she's had a fair share of fanservice characters, a number of her roles have also seen her become subject to abuse in various forms.
- Of Corset Hurts: Admitted in an interview for Klondike that she didn't have a pleasant experience wearing a corset.
- Sibling Team: She worked with her brother Dylan on his short film Down.
- Statuesque Stunner: 5'10" and beautiful.
- Two First Names: And both happen to be Gender Blender Names.
- You Look Familiar: As is the norm for guest stars in the Law & Order franchise, she portrayed different characters on the original show and Criminal Intent. Her episodes, however, also aired a day apart from each other and both featured her in the opening scene. True to the format of each series, she was only involved in the former's Inciting Incident, but had a prominent role in the latter.