(written from a Production point of view)
McElroy began his career with the horror sequel Halloween 4: The Return of Michael Myers (1988, featuring Michael Pataki, George Wilbur, and Tom Morga, with music by Alan Howarth). He later worked again with Halloween 4 director Dwight H. Little on the Brandon Lee vehicle Rapid Fire (1992, with Jeff McCarthy). Subequently, his film credits include Spawn (1997, with Melinda Clarke, and cinematography by Guillermo Navarro), Layover (2001, with Gregg Henry and Tom Wright), Ballistic: Ecks vs. Sever (2002, also with Henry, and with music by Don Davis), Wrong Turn (2003), The Marine (2006), Thr3e (2006), and then teaming up again with Little for the video game adaptation Tekken (2010, with Cary-Hiroyuki Tagawa).
In the 2010s McElroy began writing primarily for television, working as a writer and executive story editor on The Vampire Diaries, and as a writer and producer on Sacred Lies and The Night Shift.