Mallory Yarnall joined the Motion Picture Editors Guild in 2014. Since then, she has worked in the editorial department on 25 television productions, including PBS's American Masters, CBS's Survivor and Netflix's Arrested Development.

In 2023, Mallory signed on as Assistant Editor at the FX series It's Always Sunny in Philadelphia, and she has remained a part of the team there for three seasons—earning an Editor credit on two episodes: "The Gang Gets Cursed"(Season 16) and "The Gang Goes to the Ren Faire" (Season 18).

Her latest television credits also include the Apple TV+ comedy Mythic Quest (created by Rob McElhenney, Megan Ganz and Charlie Day) and the Paramount+ drama Rabbit Hole (starring Keifer Sutherland).
 
Most recently, she completed work as Editor on the upcoming independent feature film Stockholm Squad. In addition, she has served as Assistant Editor on numerous features, including the acclaimed 2017 documentary Unrest (which won the Special Jury Award For Editing at Sundance) and the 2022 reboot of Clive Barker's Hellraiser (now streaming on Hulu).