Halley Gross is a writer, famously known for writing episodes for the TV series Westworld. She will be co-writing the story for The Last of Us Part II with Neil Druckmann, which has been cited as intended to be "intense". She personally stated on her Twitter account on December 3, 2016, that she "couldn't be prouder" to be working on the game under Naughty Dog.
At PSX 2017, Gross appeared alongside Druckmann to discuss writing The Last of Us Part II. She remarked on the transition from television writing to the gaming industry, noting how connected the writer is to the programmers, designers and so on when compared to just "a single proofread for the table reading" with the actors as in television. Druckmann, teasing the audience remarked that Gross had went to her husband and revealed she had supposedly "got one of the characters pregnant". She also remarked on learning about fail states in gaming; she joked she hated having to redraft her story ideas so they are more player friendly.